maintenance issue covers a lot of areas. Shocks, fd, rd, chain, cranks, brakes, pedals, and pretty much everything you can think of for a bike.
Generally, if you are out for a round or half island ride, it would be ideal to do a thorough check on the whole bike.
I usually take out the chain, degrease it and regrease. prepare a bucket of warm water and a piece of cloth for the wipe down. pressure air...either from a can or compressor. Car polish and buffer cloth for the shine, toothbrush, paintbrush, allen keys and tire shine for the basic clean up after a long ride.
Those that are serious about biking should always learn how to build a bike from scratch, I did 5 to 6 years ago and now I can even true a wheel...albeit a little slow...hehe.
Its like building a rig from scratch...its pretty fun and you'll get "poisoned" in the process...all the expensive stuff start draining your bank. Like those obermayer wheels...drool...
Anyway, its always good to have a few LBS that you visit on a regular basis, build a good relationship and learn a lot of stuff by camping there and watch how stuff are being done. And when you need some stuff, they will give you discounts and you always get pioritize ahead of the rest of the customers when the latest stuff arrives.