One of the problems with doing user manuals as part of my day job (the WANScaler group at Citrix Systems) is that the scheduling is always so wacky. You can’t document the product precisely until it stops changing, and it doesn’t do that until the last minute. Then the documentation has to be done in a rush. Good thing I like a challenge! So I’m in a tremendous rush to get everything done for a big software release.
There are some specific techniques for making this work. The most important one is to be a bona fide expert on the product, so you already know what it does, why it does it, and why the customer should care. You can’t succeed at a last-minute rush if you’re faced with big knowledge gaps. You just need to catch up on what the last-minute changes do.