Think about this, the company I worked for required I get a physical every two years. I went to one and the nurse asked me “when did you get your last tetanus shot?” I said “beats me”. She asked if I wanted one? I stick myself with fish hooks, stab myself with old barb wire, and etc sometimes so I said yeah. She whips out a syringe from her pocket and gives me a booster shot. Said I needed one every 7 to 10 years. I was around 40 years old back then. She had 4 or 5 of those shots in her pocket. I always thought that was funny. Dad was as bad about it as her.
I was on the Hazmat team so I had to get a very complete physical every year. Everyone on the fire department had to get their shots every year. So I had several shots a year for 25 years to help protect me against all the nasty stuff we assisted people with. I haven't actually had an inoculation since I retired. My wife thinks I should get the pneumonia shot since I seem to have sensitive lungs after some of the bad chemical exposures that I had.