When I reset it's usually not because I can't easily make up the time, it's that I'm frustrated of having all red splits (wsplit) constantly. So I usually reset when I am 100% sure I can't make up even half the time I'm behind by.
I try to avoid resets, but then I also run a pretty long game at the moment. I find that resetting early in the game leads to great early-run consistency, but destroys late-game. Why reset a 3-4 hour run at 20 minutes when you may as well finish it and get the extra round of practice? That said, if I know it is 100% impossible to get an improved time, I usually give in and reset, but the runs themselves to me are more important than the time. For now...