I would say there is a variety of practices in this area. While I would take a payment on account at the time of first stage payment, I usually leave something to be collected at the end, for the reason that it is not always practical to give a fixed fee quote in stage payment situations (though variation in fees is more likely in a self-build than in a housing estate stage payment scenario). Also, I think clients like the notion that there is still something to be paid - if you are paid all your money early on, there can be a perception (unfair, I know) that I will then lose interest in the job.