I hand off to a tax expert when things are too complicated for a 1040EZ. Basically I hand off to an expert when the problem grows beyond my capabilities, same as any other kind of problem.
I'm not saying be great at everything, that's literally not possible. What I'm saying is that specialization is not antithetical to generalization. A good generalist should have areas of expertise because we can't cover everything. You don't need to be a world class expert, but you do need to find a niche for yourself and IMO the best way to do that is to simply follow what you find interesting.
> "too complicated...beyond my capabilities"
To OP's question, how did you decide that going further down the tax education wasn't for you? Was it really capabilities?
I propose that what you're really saying is that you're
a. not as intellectually curious about tax matters
b. or not concerned about the opportunity cost of your delegate being wrong
which makes it an easier choice to delegate.