Think of pretty much any show but I’ll single out Friends this time.  The show stages the important scenes where the story happens.  It doesn’t worry about the logistics of how are these people always in an apartment or the coffee house.  They work, they have to get to work/home/coffee house, eat sleep and it’s implied they have stuff going on outside of what’s shown.. But unless there is some relevance to the story those aspects aren’t shown.   In RPG terms actions that last a scene last as long as the current situation is relevant to the story.  As soon as that changes the scene ends.   

Now one player may argue why does this power last 5 minutes this time, like during a fight and last an hour next time during a travelling/investigation scene.  My answer to that question is that it’s relative to your attention, stamina, stress whatever you want to call it.  Fights burn through your reserves while travelling and talking to people not so much.

I think in terms of breaking down how long something lasts then a very specific thing like 1 action is fine.  As are it lasts a day, that’s pretty good too.  It’s when you have weird middle grounds like 10 rounds or 8 hours because 10 rounds could be all but the last round of combat and you have to track it.  8 hrs means I have to actually worry about how long did it take to get from A to B, how long did you actually spend searching for something before the fight broke out and if it’s on the cusp do you just let it go to cover the fight, maybe it ends before the fight and god help the argument if you suggest 8 hrs is up half way into the fight.