How do you make these huge changes and stay so stable?

[Jonathon McKitrick]

I'm reading the diary, as well as the roadmap for the KVA/page
requirements/requests and I'm wondering how the heck you can rip so much out
and replace it with so much new code, and still stay 'production stable'?
It's pretty amazing.  Do you guys just keep the patches to yourselves for a
while to test them, or what?

Jonathon
--
The beaten path is for the beaten man.