Also, check your local (free) papers. A lot of the people who offer this service already work for maintenance firms, as I do, and are just earning a bit of extra money.
Be aware though that some of these will overcharge if they think they can get away with it.
By that I mean if they think that you don't know what they are doing they will make the job sound more complicated than it really is.
Most of the problems encountered by home users are easily rectified by an engineer and should not be very expensive.