Depends....I put alot of miles on my bike,so it gets looked at every weekend.....It's in a constant state of "tune-up"......It gets cleaned and serviced,whatever that may be....could be just a washing or like last weekend,it got a new chain and cassette and all bolts got checked.
Tired of clicking and rubbing and dicking with your shifters?....Throw the index shifters in the trash....There,fixed that problem for ya.....
Have your wheels serviced well and you should not have to touch them unless something bad happens.
You can do this work yourself,except maybe wheels at first....Take your time,do one thing at a time so you know what that does.Just takes some practice.