Most GA aircraft flying today were certified under the old CAR 3 standards, which did not set a life-limit for aircraft components. Newer aircraft (such as the Commander 112 and 114 and the offerings from Cirrus and Lancair) are certified under FAR Part 23, which requires the manufacturer to establish a life-limit - in flight hours - for critical structures such as wing spars. For example, the pressurized P58 Baron (unlike its siblings in the Beechcraft line) is Part 23 certified and has a 10,000-hour wing spar limit. Cirrus aircraft have a 12,000-hour limit on the wing. The Commander single-engine models range from 6,945 to 19,284 hours maximum life on the wing.
So does that mean that 10,000 hours would be a ballpark figure for the life of CAR 3 aircraft? Not necessarily. For Part 23-certificated aircraft, the life-limit is what the manufacturer has chosen to prove to the FAA - the structure actually has a much greater safety margin built in. So 10,000 hours might be very conservative.