I became a convert to professional fitting when I bought a new road bike a few years ago at age 60 that came with a discounted Retul fitting. The fitter moved my cleats all the way back on my shoes and raised my seat about .5 inches, from settings I'd arrived at myself by tinkering over the years. Made huge differences, I was surprised.

He also echoed terrymorse's comments - said my hip flexors were very tight, that can increase with age or just be a natural issue. I've been doing hip flexor stretches since then. Now on longer, hillier rides I don't even feel it the next day. Not sure which contributed more, the fit changes or the stretching - I tend the credit the fit changes since I saw immediate benefit, but I think both were positive changes.