I get tested every 6-8 weeks.
Some people will think this is obsessive but so what! I couldn't care less what anybody says or thinks. I call it being responsible. It's my health and I'm right to be concerned about it. The people at the various clinics understand and appreciate my need for a clean bill of health. The checks take an hour at most and aren't a big deal at all.
I don't offer owo so I fall in the lowest risk category but the risk is still there (a tiny risk from reverse oral) so I'll continue being checked this often as long as I'm doing this job. I don't have a partner so there's no risk of passing or contracting anything there either but I owe it to myself and the people I spend time with to make sure there's nothing nasty going on down there.
The incubation period for some things might be 3 months or 6 months, but if you're an escort working throughout the year that 3/6 month incubation period is ongoing. You might have offered owo in jan, got tested in march and everything is fine as the incubation period for certain things is over but what about the owo you offered in Feb? The incubation period wont be over until April. You could be passing all sorts on to any number of people until you find out at your next check up that you've got some nasty living inside you.