Pay for what is standing, not what is promised

Each payment request should answer one question before anything else: is this much work actually standing on site? Before paying, walk the job with the request in your hand - or have someone who values building work for a living do it - and check the big items against what you can see. That check is a valuation: putting a value on the work actually done, no more, before the money moves. Paying on the promise instead, because the builder is friendly or the programme says so, quietly hands over your only real protection - a builder who is always slightly behind your money has every reason to finish, and one who is ahead of it has rather fewer.