Personally I always get a contract signed with layout of the terms in 3 to 4 pages, what my services include and what they don't and what I am responsible for, what I am not and my rates depending on what the job is and what is required for the job. One 3rd downpayment before any work gets started and then another 3rd to start the next stage and then the last 3rd before live. That way there is a mutual understanding between both parties.