It's recommended that you go ahead and get a tetanus shot before you get cut so you won't have to get one right after the cut.
If you do get cut especially cut by something rusty or step on a rusty nail you should go to the doctor right away and get a tetanus shot if you haven't had a tetanus shot in 10 years.
Tetanus is a serious thing and can be deadly so do get the shot if you do get cut or haven't gotten the tetanus shot already.