Hi Rhouse:
I'll tell you... age is not as important in determining work needed in home as much as how well built the home is.
For example, the beautiful older homes were built with painstaking detail to quality and workmanship whereas many of the newer homes are not being built to similar standards so will be needing updates more quickly than the older homes... that make sense?
Some of the condominium comlexes they put up in the 80s, for example, are just falling apart from inferior materials and workmanship.
Electrically, older homes that are 25 years or older may or may not need updating. Updating electrically in older homes is usually related to renovations, additions, and remodels not just updating because home is older.
Similarly, plumbing is not usually updated until a kitchen remodeler opens a ceiling and finds that it is best to replace older pipes from upstairs bathroom now then to have a leak occur over new cabinets and hardwood floors, etc. Plumbing work will also usually be done in relation to renovations, additions, and remodels... just like electric.
From here... all contractors are needed to repair/renovate older buildings... depends on work being performed.
A list:
Handyman
Home inspector
Pest control persons
Carpenter
HVAC contractor
Siding contractor
Plasterer
Painter
Plumber
Electrician
Oil burner technician
Mason
Gas fitter
Flooring contractor (hardwood, carpets, tile, linoleum)
Roofer/gutters
A glass repair guy
Also, don't forget the pizza delivery and chinese delivery guys at lunch time. Or the bartender needed after hours!!
Just my opinion, but the bartender is the most important guy on the list!!
Anyway, I'm sure I missed some contractors needed here... but just wanted to present my thoughts.
Let me know if want to discuss more...
MARK