I can relate to the benefit of slowly transforming highly used software. Recently, we did a massive upgrade to our forum software (the most used part of our system), changing the look, some of the feel, and some of the functionality in one fell swoop, and with the instant change, there was quite a revolt from the userbase.<p>Luckily, were able to quickly revert much back to begin incrementally making the changes to little effect. Had we kept it like that, given the response from the users, we could have lost some long customers.<p>It was our mistake for making such a huge change in one massive patch, but we've learned from that mistake.