It depends... let's say you're the leading product in the area, your users are devs, and there's a good reason behind the change, then you're probably okay to d

It depends... let's say you're the leading product in the area, your users are devs, and there's a good reason behind the change, then you're probably okay to deprecate APIs. For example, NUnit has now deprecated the "Assert.AreEqual" method: https://docs.nunit.org/articles/nunit/writing-tests/assertions/assertions.html https://docs.nunit.org/articles/nunit/writing-tests/assertio... . For me this meant running through hundreds of tests and rewriting them using "Assert.That" or sometimes using "ClassicAssert.AreEqual". I guess I see it as part of the job of being in an evolving industry.