I agree with all the comments made here. Which takes me to any new client asking for services. Does anyone ask for a retainer for "new clients" only? Just for the first month or so until you feel that this new client is a 'paying customer'? And then you could go back to your normal method of billing/collecting.
There will always be the sad fact that you finish the work for a 'new' client and then they don't have the money to pay.
So even if you take a 50% deposit up front, and you hold back the work, you still are being shorted. So would anyone take a retainer which would include besides retainer clients, hourly or project based clients?
I think this would be a way to secure payment from new clients that we have no background on at all. Especially in this bad economy. Thoughts?

Thanks!