The only practical experience I have of this as someone who was involved with the decision beyond my personal blogs was back when the UK MLP fandom was mostly on a web-based forum. (This was 2013 or so, before social media had really exploded.) We settled on either one or two weeks -- I can't now remember which, and the forum no longer exists so I can't check back. I thought it was reasonable, anyway.
Our policy was to time it from the US airdate, since (again this dates it a bit!) this was before box-set-dumping and episodes generally came out once a week. Virtually everyone watched the American releases via... unofficial means, me included. As such, we could be pretty confident that 99% of people who cared would have seen each episode within a few days, barring illness, holidays etc.
For classic films and shows... how long is a piece of string? Do you spoil the meaning of "Rosebud" or the final scene of Blackadder Goes Forth? Going back to my MLP example, though, absolutely nobody now bothers to be careful about Twilight becoming an alicorn at the end of S3, since it's a change that's instantly visually obvious and you'd have to basically avoid every toy shop in the world not to see it. So I suppose it's a case by case thing.
no subject
Our policy was to time it from the US airdate, since (again this dates it a bit!) this was before box-set-dumping and episodes generally came out once a week. Virtually everyone watched the American releases via... unofficial means, me included. As such, we could be pretty confident that 99% of people who cared would have seen each episode within a few days, barring illness, holidays etc.
For classic films and shows... how long is a piece of string? Do you spoil the meaning of "Rosebud" or the final scene of Blackadder Goes Forth? Going back to my MLP example, though, absolutely nobody now bothers to be careful about Twilight becoming an alicorn at the end of S3, since it's a change that's instantly visually obvious and you'd have to basically avoid every toy shop in the world not to see it. So I suppose it's a case by case thing.