[speedplane]

You beat me to the punch. Yes if I'm hired to work on a large, buggy, and antiquated code-base, the first thing I'd do is build tests. Many of them, both unit tests and big functional selenium-style tests. I would definitely try to setup some coverage analysis, but I wouldn't be religious about it. The focus should be to cover popular features, not lines of code.

With those in place, you can start chopping away left and right. Even if you make big changes, when you see all of those tests pass green (or blue if you're on Jenkins), it gives you a level of comfort that no careful reading of the code can supply.