When removing the original countertop, you have to treat the process very delicately. You don't want to damage the backsplash, cabinets, appliances, or flooring. After removing the original countertop, make sure that the plywood underneath the countertop is still in good shape and doesn't have any water damage. If it is damaged, then you'll need to replace it. If it's not damaged, then you can keep it and put a new countertop on top of it.