I'm an impatient fuck, but it depends on the platform.
If I'm playing on Steam, I give each game 30 minutes to woo me before I bounce. If the tutorial is still going at that point, it's being unquestionably refunded. If I'm having trouble but I'm more frustrated than I am interested, it's also being unquestionably refunded. If I bought it thinking it was one thing and it turns out to be another, it's another unquestionable refund.
Those last two reasons are why I no longer have Rain World (despite the unending raving about it making me curious even after I refunded), and that first one is why I no longer have Monster Hunter World. I'm sure both of those games are great for some people but I bought Rain World thinking it was a difficult Metroidvania (when in reality there was a much heavier emphasis on survival as opposed to exploration), and Monster Hunter World will not shut the fuck up and let me learn by doing already.
If I'm playing something I bought for a console, I'm very very hesitant to refund. I'll often get 20+ hours into a game I'm not enjoying before I give up and bother refunding. Might have to do with sunken cost, especially since I exclusively buy physical copies of games whenever it's possible, might have to do with not having a 2-hour time limit on my gameplay before I can no longer return it... not sure. Doesn't really matter tbh.
If I'm emulating an older game or otherwise playing something on my PC without paying for it, I tend to hover around 2-5 hours before dropping it. If the game is shorter (especially if it's, like, NES old) then it tends to be more of a 1-3 hour thing.
I'm curious as to whether this is just a me thing? Dunno if anyone else alternates their time limits based on context. I'm sure plenty of people out there do but I'm not sure how many.