Firstly, the OP is a troll or a fucking twat or a visitor from mumsnet. He started "thinking about his first punt" months ago and has done fuck all. I'm not going to post for his useless wanking self.
As a question for
punters it's reasonable enough but similar to 'how long is a piece of string?' (And why aren't you visiting a medical site instead of UKP for the information?)
Simple answer: it's not common. I think it is mostly important for guys with an active O/H. The chances of getting an std from a prossie if you are using a condom properly are infinitesimal.
If you use a short-arse condom you're still protected from fluid transmission but not skin-to-skin infections like hpv, herpes, that are unlikely to be but could be picked up that way, so find out which condoms cover your dick. I think you're less likely to get crabs off a prossie than a lowlife civvie who hasn't noticed cos prossies mostly shave.
The slight ---- what, 1 in 500 -- chance of getting the clap with OWO can be avoided by married men simply by not having OWO. For anyone else, although it's a personal choice, all it really means is a visit to the clap clinic and some shots, plus no sex till it's cleared up.
The risk of gonny with a pro$$ie during OWO is exactly the same as with a civvie -- biology doesn't care about exchange of cash.
The slight inconvenience, again looking at extreme cases and not exactly the sky falling in, is triggering an NSU such as thrush in your OH. Anyone can get thrush even without sex but women's fannies are more susceptible. So if you shag someone with thrush then stick your dick straight in your wife it may trigger her own yeast imbalance. Not a big deal, usually treated (men or women) with Canestan. Of course, if your OH only gives you a shag once a year and only gets thrush after that she may look at you squint-eyed, but it could just as easily be an under-exercised fanny!
On a serious note to the time-wasting OP: please note that it is very dangerous going out of the house to visit a prostitute. It can affect your brain, and could result in serious hospitalisation due to not looking properly ... as you cross the fucking road.
Here's a website for little boys, or elderly twats with no sex education (both of which should stay away from sex until their brains have developed:
External Link/Members Only