I used to think it was a waste of money. I did not do risky things like ski or play contact sports. I didn't even like running because I was always afraid I'd slip and fall and get hurt badly. I got hit out of nowhere with my disabling event; my body just decided to turn on me. Your colleague is lucky he was able to return to work. I met several people under 40 with spinal cord injuries when I was hospitalized for months who were completely paralyzed from the neck down from car crashes, pool accidents, stair accidents, slipping on the floor. I have a small regret of not increasing my policy when I was making good associate orthodontist money a few years prior to the incident and had the option to increase coverage. I didn't increase it because I was like "why, I can think of so many more fun ways to spend this money." But I had no idea what the future had in store for me so I don't dwell on the regret.
One does not have to have disability insurance. If you are wealthy enough to maintain your lifestyle without your dentist paycheck, then why bother. If I didn't have it, we would not be on the street as my spouse works full time. But it definitely helps maintain a better lifestyle for our kids.
