I'm considering 05 s40, the owner tells me that the timing belt has been replaced twice, the car has 130k on it. I'm confused with that kind of mileage why would that need to be changed twice, could it be that it wasn't done correctly the first time?
Timing belt is due at either 105k or 120k based on mileage. If they didn't replace other components, such as the tensioner, or the person replacing the belt was off by a tooth, timing would have gotten messed up. They could easily have just pulled the belt, reset timing, replaced other parts, then put the belt back on. But probably safest just to swap on a whole new belt. Belts are cheap, it's the labor that's expensive.
I'm at 136k miles and mine has been replaced twice for that exact reason. Timing belt jumped a tooth after 20k miles, so I just had the dealer replace it.