I don't. I have no illusion that i will understand a large code base, even one i started, and have been using for 10 years. But when you have a hundred develope

I don't. I have no illusion that i will understand a large code base, even one i started, and have been using for 10 years. But when you have a hundred developers constantly adding code all the time, you are not going to know it all. Find and fix the parts you need to work on. Don't worry about the rest.