By all means, get a layer. If you are a professional freelancer, you must someone that can:
- make sure you get paid
- do the unpleasant talks for you when business get sour
- protect you from liability
Freelancing is hard enough without spending mental and emotional energy with this kind of thing. I could not put it better than Mike Monteiro:
http://shelby.tv/video/vimeo/22053820/2011-03-mike-monteiro-f-ck-you-pay-me