It kinda depends when the club starts and finishes. Our clubs close at 3 a.m. or earlier, and a lot of the crowd might have only been in for 2 or 3 hours by that stage. It would make little sense to ease up for the last 45 mins or hour in this kind of scenario, however if you're talking free parties or longer running events then I think it's good to bring it down towards the end... in many ways it's the natural thing to do. I've noticed that promoters or organisers will often program their events like this, with the really banging stuff going until 5 or 6 a.m. and the last few hours seeing a bit more of a drop, depends what country you're in though :)

If it's outdoor it's nice to let your head groove a bit, or for the music to be less banging or intense when the sun's coming up. It really depends on the night I suppose, every party or crew may be different or have a different appetite towards their music. The best sets I've heard end a night though (i.e. 7 or 8 a.m.) were old skool sets, or something a bit housier.

Good topic btw.