Because of a long layover I will need a hotel from around 6am (ideally checking out around 1pm but 12pm would still be ok). Am I safe booking a room for the night before?

In other words, will hotels usually cancel reservations if the guest hasn't checked in by some time the night of the check-in date? Or will reservations be alive until the checkout time the following date?

I'm looking into Priceline for this stay, so I'd like to know what's the regular practice. TIA ^