Depends on the show and how its written. A really tense show that builds and builds tension across the season is probably better kept short. A show where the episodes don't really carry across any themes can go as long as it likes, the seasons don't matter.
I miss 20 episode seasons but I understand why that's not super feasible and was unhealthy for actors. You just get so much more time to get to know the characters.
For me, it really depends on how long each episode is. I would say the sweet spot is somewhere between 6-10 hours worth of content, regardless of individual episode length. Any less feels like there isn't enough time for character and/or plot development, and any more, and I start to forget all the plot details. As it is, with many shows having 1-2 year gaps between seasons, I often feel I need to repeat the previous season just to remember what all was going on.
"It depends" on the story, between 6-12
Usually 6-8, most series that stretch the story over 10-12 episodes make them unnecessarily short, or put unnecessary fillers in. Either is annoying.
For long form live action shows like "The boys" usually 8
For animated shows, 12-24. As long as story progression can actually fill it.
My reasoning is just that it helps determine what to watch given available time.
Really my ideal, for shows I like, it would either come out as a full finished show (all seasons all episodes) so I can have a complete story and not have that annual wait. Or it would be a weekly ongoing, similar to the Simpsons or south park.
11
Six seasons and a movie
It really depends on the show, it's scope and the characters. When a show adds more, important characters, time will need to be dedicated to developing those characters and playing out their story arc. Also, when a show is telling a story which encompasses a large scale, with many sub-plots, that all needs screen time. And all those sub plots and threads need time to really pay off. There is also a matter of scale for events. If a particular event has been built up, over many episodes or even seasons, it probably needs to play out over a couple episodes to give it the scale and gravitas which is expected of it.
Ultimately, the number of episodes per season is really part of the story telling decision. And that decision is going to be different for different shows. But, I'd argue that, if show writers are finding themselves turning to played out tropes like "us, but evil" or "time travel to the current time" or "musical numbers in a show which isn't a musical" then there's probably too many episodes that season.
These days high production costs and long 2 year hiatuses has not resulted in better writing or follow up seasons feeling worth the wait.
So I'm in the camp now of 8-10 episode "mini series" like Fargo or Shogun. Or kdrama type approach of 16 episode series released 2 episodes weekly and concluding at the end.
For me it depends on the genre and plot. Noir/political/scifi thrillers can run up to 10 episodes. Straightforward love stories, daily life, and coming-of-age stories should be kept to the minimum, like 6 episodes. The recent trend I also noticed is pacing. If your story can be told in 6 or 8 episodes, don't stretch it to 10, regardless of the genre.
