I follow Will's routine almost exactly. He made an important point - stretching the new strings means far less retuning, very important if it's in the middle of your set.
In addition, I don't snip the strings straight away but loop them (tidily) to retain the full length - this is because I've sometimes had new strings snap at the saddle/bridge almost immediately. If you have the full length you can easily remove the ball end from the broken bit and knot the long string to it. A lot better than having to replace the old string.....
After a day or so I snip 'em.