The longer jobs, I guess, are the sort of stuff I tend to do pre-winter (regreasing seat post, bb threads, steerer). I'd reckon on a cable change every year too, at least on a regularly used bike, and that can take a while, depending on how finicky the routing, indexing &c is.
I do most jobs myself, although I'd balk at fitting a headset, or facing a BB shell. I think one of the joys of bicycles (pre-electronic shifting, at least) is that they are, mechanically, very simple.
I like doing the maintenance I can do (as well as building wheels, &c) but some people don't, and that's fine - all you need is an LBS you can trust to do the work properly for you.
There seems to be an odd, hair shirt mentality around some things in cycling (the racers all want everyone to "suffer", the shed grumps all want everyone to sweat over every little task themselves) that I don't entirely understand. You're not a bad person if you don't do your own maintenance. It makes sense to know how to do some roadside repairs, but even then, if you'd sooner not and have a viable bail out method if you need to abandon a ride, so what?