Fixing the car

Why does the car always break down? My hubby is always trying to fix the car. My job just kills the car. Infact he is out there fixing it now. He made me run and pick him up a new tire, they are so expensive. But needing the tire, I went and got it. At least I didn't have to take the kids with me. They were playing at there friends house. He is fixing the lower control arm, and I believe something called the half-shaft? I don't know much about cars, other than it costs a lot to fill in gas, and a lot to keep running.