With a reconditioned hybrid, things are a bit different because you really don't know how the battery was treated before. If the car was used for delivery work or as a taxi, maybe with constant charging in less-than-ideal conditions, the battery could have degraded more than normal even if it's only 5-6 years old.
That said, modern hybrid batteries are pretty solid. The real issue is that you won't have a clear picture of its actual condition - so before buying, get a proper diagnostic done by a shop that knows what they're doing (not the first mechanic you find). Check if the seller has data on charge cycles or battery health, even though this info is often hard to come by. A battery degraded to 70-80% of its original capacity still works, but it'll burn more fuel and lose some range in electric mode.
Warranty matters: if you buy from a reputable dealer, they often cover the battery for an extra period. Without a warranty, a full replacement could cost a lot, though less than many people think. Weigh it all against the price of the reconditioned car and whether it's really worth it compared to a slightly newer model with a fresh battery.