[dem00n]

I've driven some cars that have stock shocks and are past the 100k mile mark. It depends on the quality of the shock, where it's driven and how many miles are on the car.
I have over 50k on the stock shocks and we have some really shitty roads in New York, even worse in the winter. I'm really impressed on how they held up, since 50k tends to be the magical number around here for passenger cars.

But as most here, if stock struts are starting to misbehave...time for an upgrade.

If the winter is really harsh near you, swapping out aftermarket suspension for OEM seems like a good idea if you have the time and experience.