[jgalar]

IMO, it really depends on the context. If you are working with people who share your assessment of the current situation (both business and technical folks) and want to improve it, you'll have a great chance to learn from others' (and your) mistakes.

However, constantly putting off fires, under the gun, in horrible code bases, is probably not a good way to learn how to design software... It's a good way to learn how to debug and reason about problems, which is also a valuable skill to develop, though.