Labor-only renovation / norms on payment & paperwork

[Lisa Caro]

Hi! My contractor is requesting a third of total renovation cost as down payment - but I've hired him for labor only (I'm providing the supplies etc). I would feel more comfortable paying a normal labor rate as we progress. What's reasonable in this case (when/how much)?

Also, can I request a copy of contractor's ID? No idea if I can legally request that, but this is my first renovation project and I'm just nervous.