Here and there I hear talk from people wondering why "Heroes", "Veronica Mars", "Battlestar Galactica" and other great shows take long breaks in the middle of their seasons between a set of new episodes and any remaining new episodes. While not technically 'on hiatus' (the term applies only to shows where production has been shut down for some period), these breaks in broadcasting new episodes are primarily a marketing ploy, pure and simple, for production companies and/or networks who are culturally biased against producing more episodes for a given season.
Let me explain further: in the USA, it has developed over half a century of television production that a standard season of TV programming consist of 24-26 episodes. There are many theories as to why this has developed this way (26 episodes is exactly half the year, etc) but the fact is, by now it is an ingrained part of the culture that a season is only so many episodes long. So whenever industry news reports talk about a show/actor/director/whatever being "signed for a full season", they're almost always talking about 26 episodes. There's no reason that a studio couldn't produce more episodes for a show getting great ratings other than this tradition, but studios tend to reluctance when considering producing more than this, given that networks rarely if ever order more than this...and the inverse also applies: networks are disinclined to order more than that because who produces more than 26 episodes?
Now, since 26 episodes allow for broadcasting new episodes for exactly half of a year, the TV networks have developed various strategies over the decades for releasing the content. For most of the history of the medium, the tradition was to start a TV season at around the time that school started up again in the Autumn, and air a block of new episodes once a week at the start of that season (say, 5). Then you would continue by airing a new episode every 2-3 weeks after that, spreading the rest of the year out with re-runs and the occasional event program which 'pre-empted' the show (holidays, sports broadcasts). The season typically ended at the beginning of the traditional school break for Summer, presumably on the assumption that families will be out on vacation together, so ratings would suffer, so why air new programming at that time?
While the tradition of the television season's start and end continues (albeit somewhat loosened), in the last decade or so, the networks have become much more competitive over advertising dollars (in part because the money/audience is thought to be going away to other media outlets - web sites, cable, video games, hand-held devices), which has resulted in two phenomena:
1) Networks are cancelling shows at the drop of a hat (relatively), if the ratings go south for even two weeks in a row.
A quick note on TV ratings: ratings numbers are not judged objectively, but relatively - that is to say, it doesn't matter how many millions of viewers are projected (since ratings are all extrapolated into the millions from a much smaller, representative portion of the population) to watch your show...what matters is how those millions rank versus the other networks. A given show could have 10 million viewers every week and it would be cancelled if the other networks had fluke or event shows that got more than 10 million for a couple of weeks in a row.
The repercussion of this tendency to cancel is that networks are particularly prone to ordering only partial seasons for most shows - six episodes, say, where the fate of the show will be based on the ratings for the first two episodes, and it can be yanked off the air to be replaced by a less expensive program for the remainder of the year (see "Smith" for an example: link). This makes sense from a raw financial standpoint, as it allows the networks the freedom to ax the under-performing shows without losing the company as big an investment as if a full 26 episodes had been ordered.
2) The longer break allows for a number of things that are advantageous for the networks compared to the older, intermittent-broadcast-of-new-episodes method:
First, such breaks often coincide with the end of the initial order of episodes and the order completing the full season (not the case with 'Heroes' but often with others) - and the advantage for the network for ordering partial seasons has already been explained.
Second, such breaks allow for more complicated work to be added to the remaining episodes in post-production (many shows will show an increased use of CGI in the post-break episodes for a given reason).
Third, such breaks allow the cast (as well as writers/directors, sometimes) to go on extensive publicity tours to shill for the program. While the shooting schedule isn't affected by having a longer break or not (the shows are typically not on hiatus during this period, remember), such concentrated publicity work can build audience excitement about all the remaining episodes, and the thinking is that that will increase ratings for all the episodes, not just the ones that come during the end-of-season sweeps from April-May (though astute viewers will notice that the last five episodes of "Heroes"' first season and "Veronica Mars"' third season fall precisely during these sweeps).
Finally, a long break like these allow for networks to attempt to launch second-string shows, like, say, 'The Black Donnellys' (link) or dopey reality TV dross like 'The Search for the Next Doll'.
So, frustrated and/or losing interest in your favorite programs during long months where no new episodes are aired? Join the club! But realize that the networks are doing it to protect themselves and to drum up your enthusiasm for the show with a little suspense. So far, it seems to be working for them, and it's unlikely to change unless the whole system of TV ratings is revamped.
Let me explain further: in the USA, it has developed over half a century of television production that a standard season of TV programming consist of 24-26 episodes. There are many theories as to why this has developed this way (26 episodes is exactly half the year, etc) but the fact is, by now it is an ingrained part of the culture that a season is only so many episodes long. So whenever industry news reports talk about a show/actor/director/whatever being "signed for a full season", they're almost always talking about 26 episodes. There's no reason that a studio couldn't produce more episodes for a show getting great ratings other than this tradition, but studios tend to reluctance when considering producing more than this, given that networks rarely if ever order more than this...and the inverse also applies: networks are disinclined to order more than that because who produces more than 26 episodes?
Now, since 26 episodes allow for broadcasting new episodes for exactly half of a year, the TV networks have developed various strategies over the decades for releasing the content. For most of the history of the medium, the tradition was to start a TV season at around the time that school started up again in the Autumn, and air a block of new episodes once a week at the start of that season (say, 5). Then you would continue by airing a new episode every 2-3 weeks after that, spreading the rest of the year out with re-runs and the occasional event program which 'pre-empted' the show (holidays, sports broadcasts). The season typically ended at the beginning of the traditional school break for Summer, presumably on the assumption that families will be out on vacation together, so ratings would suffer, so why air new programming at that time?
While the tradition of the television season's start and end continues (albeit somewhat loosened), in the last decade or so, the networks have become much more competitive over advertising dollars (in part because the money/audience is thought to be going away to other media outlets - web sites, cable, video games, hand-held devices), which has resulted in two phenomena:
1) Networks are cancelling shows at the drop of a hat (relatively), if the ratings go south for even two weeks in a row.
A quick note on TV ratings: ratings numbers are not judged objectively, but relatively - that is to say, it doesn't matter how many millions of viewers are projected (since ratings are all extrapolated into the millions from a much smaller, representative portion of the population) to watch your show...what matters is how those millions rank versus the other networks. A given show could have 10 million viewers every week and it would be cancelled if the other networks had fluke or event shows that got more than 10 million for a couple of weeks in a row.
The repercussion of this tendency to cancel is that networks are particularly prone to ordering only partial seasons for most shows - six episodes, say, where the fate of the show will be based on the ratings for the first two episodes, and it can be yanked off the air to be replaced by a less expensive program for the remainder of the year (see "Smith" for an example: link). This makes sense from a raw financial standpoint, as it allows the networks the freedom to ax the under-performing shows without losing the company as big an investment as if a full 26 episodes had been ordered.
2) The longer break allows for a number of things that are advantageous for the networks compared to the older, intermittent-broadcast-of-new-episodes method:
First, such breaks often coincide with the end of the initial order of episodes and the order completing the full season (not the case with 'Heroes' but often with others) - and the advantage for the network for ordering partial seasons has already been explained.
Second, such breaks allow for more complicated work to be added to the remaining episodes in post-production (many shows will show an increased use of CGI in the post-break episodes for a given reason).
Third, such breaks allow the cast (as well as writers/directors, sometimes) to go on extensive publicity tours to shill for the program. While the shooting schedule isn't affected by having a longer break or not (the shows are typically not on hiatus during this period, remember), such concentrated publicity work can build audience excitement about all the remaining episodes, and the thinking is that that will increase ratings for all the episodes, not just the ones that come during the end-of-season sweeps from April-May (though astute viewers will notice that the last five episodes of "Heroes"' first season and "Veronica Mars"' third season fall precisely during these sweeps).
Finally, a long break like these allow for networks to attempt to launch second-string shows, like, say, 'The Black Donnellys' (link) or dopey reality TV dross like 'The Search for the Next Doll'.
So, frustrated and/or losing interest in your favorite programs during long months where no new episodes are aired? Join the club! But realize that the networks are doing it to protect themselves and to drum up your enthusiasm for the show with a little suspense. So far, it seems to be working for them, and it's unlikely to change unless the whole system of TV ratings is revamped.