I would say it depends on how much time and money you have. I started on bikes as a student. So to save cash I did all the work myself. Over time I accumulated all the tools and know-how to maintain my bikes. The last two bikes I built from ground up.
So, yeah. I guess it depends on how much time and cash you have. If you have plenty of income and no time, because you're busy working, then help out your local bike shop for sure! For me, it is already too late. I do all the work myself, and for sure I would like to open a bike shop so I can help all those out there that don't have the time or need the help!
cheers