The above talk about temptation to spend it, quite rightly, but there is always a security issue as well. You will find plenty of comment on UKP about that issue.
If I am seeing a girl for the first time I will tend to go in with as little valuable stuff as possible, no wallet full of credit cards, just the right money, only my punting phone etc etc. This is especially true if the girl has not been reviewed on UKP.
Once i know the girl I relax this and just wander in with my wallet etc.
However two girls that I have met (one of them several times) and I thought OK then turned out to be thieves, one with someone else on here soon after I saw her and the other with me.
Essentially this, what RedKettle says, but I extend it to cover all punts. Doesn't matter how well I think I know the SP or how many times I've seen her. Just no.
I take the correct cash, my car keys (have no choice), punting phone (cheap ass Nokia, worth nothing and disposable)and wear my watch. The watch is waterproof and doesn't come off even if I have a shower. Everything else, wallet, house keys, my main and valuable smart phone etc etc is locked in the car.
A note chaps, the punting phone saved my ass one day followed a great shagging session in a top floor apartment. The building security needed a pass code to make the lift work. The lady in question gave me the code as I was leaving, but in my post de-spunked state of bliss it went in one ear and out the other. Didn't realise until I was in the lift and couldn't get it to move or open. Quick call to the SP and I was good to go.
Back on topic, this was something I learnt from a long retired Notts escort. I only saw her twice, but second time, after we had fucked a couple of times she offered me a shower, which I took as it was lunch time and I was due back in the office. Being newish to be the game I left my wallet and car keys in the bedroom on her bedside table. I came out of the shower and, to give her absolute credit, she pointed out she could have cloaned my cards and copied the car keys. She hadn't obviously, but she did say something like "not all girls are as honest as me".
Better safe than sorry in my opinion. Anyway, it just becomes one less thing to worry about when what you should be thinking about is shagging the arse off some cutie.
Think about it, I'm sure all seasoned punters can think of a punt with a well reviewed SP that has gone to shit. I had one with another very well reviewed and now long retired Notts SP just before she disappeared for good. The reviews all said "great shag", "goes like a barn door", "always well presented and gives an excellent service". What I got was half pissed and coked up playing fucking house music at full volume. Pretty much my worst punt, because I couldn't even get it up for her. These days I would have walked straight away.
Anyway, point being, would I have left my wallet lying around or any other valuable item? Would I fuck, I'd be too worried that the powder monster might see it as an easy path to her next batch or marching powder.
Only take the bare minimum cash, valuables etc etc.