When was the last time I had sex (1 month, 1 week, 1 day, 1 hour ago, etc.)
How was foreplay (if foreplay was amazing, then I have to double the efforts in not cumming)
How long I want to last (I can kinda control it, but there are situations where once I'm off the edge, it's done)
Position and things being done to me (if I'm fucking a statue, then I can last as much as I want, but if I'm being touched, kissed and licked all over, then I can count the seconds)
Anywho... anything between 5 minutes and 40 or so. After that I get tired, and I appreciate the effort of people working. The most I've been doing it has been 2hr. I must admit it got boring at the end. There are so many possibilities in a 1:1.
If foreplay is particularly good I honestly prefer to just actually cum during foreplay, so I can start sex in round-2 mode and last quite a while. Instead of going inside her already on the edge of blowing my load.