I changed the locks and the deadbolts and installed a couple of new deadbolts on my doors. You do need a key hole saw to do a dead bolt.
My XABF was FURIOUS when he found out I had changed the locks. "Why did you cahnge them 'against' me" he said. I told him that it was considered "common practice" for a woman living alone to change the locks when someone, especially a S.O., moved out.
Found out later he went on a tear over this when he got to work that day, flinging his now useless keys across the office. Shortly after this he was "laid off" with no hope of recall.
I am so GLAD he is GONE. LOL