Now that you are educated on the hinge sizes, hole patterns, and types of hinges for residential use, you need to start counting your doors. Once you have determined how many interior and exterior doors you have along with the types and sizes of hinges you need for every door, you are ready to go shopping. A couple things to make a note of before purchasing your door hinges:
Most doors have three
Most hinges today are sold in pairs.
A pair of hinges is two complete sets of hinges as displayed below. Unfortunately, if you only had to replace hinges for one door, you would need to order two pairs of hinges.