I'm an Engineer. A proud graduate of Georgia Tech. I've been wrenching since 1970. I grease all my threaded fasteners when I assemble or repair a bicycle, car, tractor or, boat. The main reason is so I can disassemble it and repair it again in the future. Have you ever tried to loosen corroded lug nuts off a wheel during a breakdown on the side of the road with no hope of changing a flat tire? While your girlfriend screams at you for being an idiot? Then, having to pay a tow truck & garage $200 to do a simple repair? Grease can help that.