I think the idea of bare and throwing caution to the wind over sensible thinking is fetishized. Lots of people are here living out a fantasy only and are not being realistic or sensible about making smart choices. However, The fetish exists.
Smart choices means different things to everyone. For some it's condom every time, for others it's for a time period or until a test is taken, and for others it's about selecting the right mate up front or trusting a partner. To each their own and be safe please!
For me, I will not deny that bare sex is seriously HOT. The feeling of intimacy and taboo is very much heightened, and I like pleasing a man on a level where he knows he can have me in that deeply intimate way. My husband also loves the idea of bare being a bit sluttier and nastier as the creamy mess after is taboo to leak out of a married woman.
For us the answer is not simple. We need a guy to show some commitment to longevity in being a partner. We also require a full std panel test before it's even considered. Finally, there is the pregnancy risk issue, so I have to consider being on a contraceptive at the time so me. Don't go screaming running. Lol. That said, no magic number, but a feeling based on every situation.
All that said. It SUCKS when you lose a long term playmate and have to go back to condoms for play. I much prefer bare, but value my health and safety overall.