ohh I think it would depend entirely on the stairs, but they would be able to manage most stairs, depending on the setting and what kind of hooves they have! As obviously a draft-type taur may have more trouble keeping their big ol dinnerplates gripped onto some narrow stairs than a mini would with their delicate little tippers who could probably manage stairs that would give humans trouble!

But I think the biggest factor would be how steep they are, if you want to make sure any centaur will be able to climb your stairs, just make em shallow and then they’re only slightly more slippy than rough terrain!

but the steeper they go past 45 degrees or so and you’re closing in fast on a ladder, and we’ve already established how that goes for centaurs (NOT GOOD. TOO MANY LIMBS)