Делать что-то – дело хорошее, но бывает, что ...
To express the idea of "it's all very well doing A, but sometimes it's best to do B", I wonder if the phrasing above sounds idiomatic enough.
In English, we commonly say something like:
It's all very well doing A, but shouldn't we do B first?
{or}: It's all well and good/dandy to do ..., but ...
How do Russian speakers commonly express this idea?
Your rendering is OK.
I'd only take issue with closely placed cognates делать ... дело хорошее. In Russian stacking up cognates is considered poor style.
Maybe a more idiomatic example could look like
Смотреть фильмы - это/оно конечно хорошо/чудесно/замечательно, но может (быть) сначала нужно/стоит сделать уроки?
The phrase дело хорошее to my taste sounds better next to a lone noun (noun phrase) or an infinitive
Футбол - дело хорошее, но...
Жениться - дело хорошее, но...
