You are not required to use the add-a-fuse when hardwiring your dash cam. You can wrap the wires around the leg of the fuse numerous times so that the connection is tight and secure. However, by using add-a-fuses, you will turn one fuse slot in your fusebox into two for a cleaner install and added safety.
Before installation, check with your hardwire installation kit to see how many fuses you will need. If you use the Thinkware, VIOFO, BlackVue, or FineVu hardwiring kit, you will need two fuses (one for constant and one for ACC). If you are using the Nextbase hardwiring kit, you only need one add-a-fuse for the ACC wire.
Which add-a-fuse is right for my vehicle? That depends on the car that you drive. You can either consult your vehicle owner's manual, Google the answer, or consult the dealership where you've previously purchased the vehicle. The BlackboxMyCar Essential Install Package comes with all four types of add-a-fuse (ATO, Mini Fuse, Low-Profile, and the Micro 2)