You don't have to use the same people to develop, document and train. Most of the time it's a very bad idea. Also, each change in the dev environment doesn't k

You don't have to use the same people to develop, document and train. Most of the time it's a very bad idea. Also, each change in the dev environment doesn't kick off a bunch of admin. However, each change in a live environment with hundreds of thousands of customers, who in turn have businesses with collectively millions of customers, should be as close to perfect as you can get. You just can't get that if you only document something up to two months later.