simply put: because they have to go somewhere.
The average hour-long drama has about 24 episodes each season. The "season" runs from September until May. That means, that in the about 36 weeks or so that the season runs, there has to be about 12 or so weeks to fill in with something other than a new episode.
How this issue is dealt with vary's show-by-show.
"24" has opted to wait until January to start each new season, allowing a straight run week-by-week of new episodes until the end. On the plus side, you don't have to worry about repeat weeks once the season starts. On the negative side, it means that instead of an already-painful 3 month break between seasons, you now have 7 months of waiting to see what happens after the previous season's huge cliffhanger. They essentially put the "rerun weeks" before the start of the season (Sept-Dec).
"LOST" has a lot of vocal audience members complaining about rerun weeks. For the first two seasons, the rerun weeks were spread fairly evenly throughout the season, meaning there were many times where there would be a 2 or 3 week gap between new episodes, and fairly often. On the plus side, viewers didn't have to wait until January to see the start of a new season, and there weren't really any HUGE gaps between episodes. On the negative, it was really tough to keep track of when it was a rerun week and when it was a new episode week.
THIS season, in order to try to appease those vocal viewers, ABC is trying something a little different. They still started the season around the usual season start, and will air the first 6 episodes 6 weeks in a row back-to-back. When the 6th episode airs on Nov. 8th, ABC will hold off on airing any new episodes until Feb. 7th, and from there air a new episode every week all the way through the season ending in May. They've basically split the season into two parts. On the plus side, viewers will no longer be wondering what weeks have new episodes and which don't. On the negative side, with all the rerun weeks being bundled up together, this means a whole 3-month break between the 6th and 7th episodes. Remember, the non-new epsiode weeks have to go SOMEWHERE.
Sweeps months occur about every 3 months: November, February, May. These are the months where TV stations pay heavy attention to the viewer numbers of each show, and from there determine how much to charge for advertisements on each hour. If ABC sees that 9PM-10PM on Wednesday nights has been gaining viewers, they can use that to charge advertisers a little more to air their commercials during that hour, and so on and so on.
In order to help bump up the ratings during those times, TV execs tend to try to put the most intriguing shows on during those months. This is why you'll see the season's BIG important episodes air in those months: Season Premieres, Season Finales, etc. You'll also notice February is full of big ball games, and tons of award shows. It's alllll about advertisement dollars.
This is also a reason why you see rerun weeks generally occur during the non-Sweeps months (like October). They want to save the really good episodes for Sweeps Months.
Hope that helps a bit.
hope this helps...
