Wolves and sheep out there.
For new girls:
You go first, you get rewarded big time, maybe 10% of the time, but you can find an enthusiastic, new to the game, happy to please WG if if you luck out.
You wait too long, a trending/overhyped WG may already reduce the level of service as she's burnt out, works too much or has plenty of clients anyway.
It all depends on your risk profile and willingness to squander money.