We have had a relatively painful experience with some work recently completed by Builder. Visual and often simple stuff has been off, very obviously done wrong and had to ask a few times to be corrected. Now its done and dusted barring cleaning up mess. I have a jarring feeling that there is the potential for some problems we are not aware of ie Plumbing or Electric, giving the problems there has been in general. What is the maximum amount of time and reason I can have for delaying final payment approx. 23 % Problems have been raised and always shot down as emanating from another source. Obviously I hope its all good and its just a bad feeling but we don't want to be stuck with problems down the line and finding it difficult for him to take responsibility of fixing them (if it comes to that)