I watched a review of the TNG episode “Thine Own Self” a while ago where it was mentioned that Picard doesn’t appear until the very end after Data gets back to the Enterprise, after all the scenes of Crusher having the bridge and Riker observing Troi taking the test to becoming a commander. They suggested that Patrick Stewart may not have been around for most of the filming but they needed him to appear at least a bit in the episode because it was in the contract.
Is this a common thing? Yesterday I was watching DS9’s “Paradise Lost” and couldn’t help but notice that Bashir only has like 3 lines on the Defiant and could easily have not been there. But Quark doesn’t appear in the episode at all.
But if Armin Shimerman didn’t need to be in every episode they could easily have cut him from the episode “Duet” because the only line Quark has is him wondering whether Bajoran survivors of a labour camp like to gamble.
Maybe I’m just thinking too hard about what happens behind the scenes instead of just enjoying the show.
It’s also a time management thing. It’s usually hard for an actor to do multiple projects at the same time (shooting days can be kinda intensive). So when they commit to a project, they want to know they aren’t wasting their time.
If they say yes to one project it would mean they have to say no to another project, but they only get paid based on appearance. If one project pays more per appearance but then has them only appear in 1 or 2 episodes, they may have said no to a project that pays less, but would have earned them more because they would have more appearances. It’s often not known in advance whos role gets how much screen time and how much shooting is involved.