The only way to work with Sugar Babies is PPM.  While in LA $500 is on the high side, even multi billionaires like Donald Sterling know PPM is the way to go, never monthly! ....

http://www.thesmokinggun.com/file/sterling-sex-deposition?page=6&fbclid=IwAR376as7Axq8O2fiDDylzjazGJHYDCfQh8fscE0Khspy0LPdlG-WIUltyAU

at least in my opinion and experience.  When you give a SB $$ in advance, two very negative psychological results are inevitable.  First, she feels obligated.  Maybe she's not in the mood or would rather do something/someone else, but you paid her and she feels obligated and pressured.  That's not conducive to her showing up bright eyed and bushy tailed, eager for your company.  Second, you start to feel entitled.  As in, I paid her, she has to show up, that was the deal. Both the obligation and the entitlement are buzz kills.  When you do ppm, at the very least you know that when you both show up it's because you both actually want to be there. just my $.02

She absolutely HATED being a hooker, and I ended up giving her a job for which I grossly over paid her, but with the understanding that I could pretty much have sex with her whenever I wanted to.

 
As I am sure you already guessed this arrangement worked out HORRIBLY until I changed the rules. It seemed like she would come up with every excuse in the world in order to not have sex, which at first I understood because she had been "managed" as a hooker and was very high volume, her poor little coochie most definitely needed a bit of a break from fucking all day every day, but after a while the arrangement just stopped working for me. What I did to change it was to cut her "real" pay down to $10 hr which was enough for basic survival, but I gave her a "bonus" of fifty bucks every time we had sex. It worked like a charm, I was still in my late forties and I could fuck several times a day and that's exactly what we did. She ended up making about a grand a week from me. lol It's funny, I've known her for thirteen years now, we were even real BF/GF for a while and now we are more FWB's on the rare times we see each other, but we still use the term "bonus" for every time we have sex all these years later. I am sure I have had sex with her more times than any other woman in my life, we fucked about a dozen times a week for over a year. lol

Great story Gambler. That was nice management on your end.