You might take the timing belt cover off (one 12mm bolt) and
inspect the timing belt. The Bay 13 staff recommends changing at
5 year interval or 70K miles. Volvo says 70K miles. The build
date of the car is in the passenger door frame (my 1998 S70 T5
was actually built Jan 1997 so the car could be older then
you think).

You might also consider a subscription to http:/www.alldatadiy.com
for @5/uear. You get service info and Technical Service Bulletins
(and recalls). The TSBs keep you up to date on known problem areas.

I'd also watch the brake pads. They don't squeek or warn you
when they wear out and you don't want metal on metal. Brake
jobs on Volvo are easy following Bay13 instructions. Online
discounters (like www.volvoparts.com) sell the parts at good
prices, too.