I signed up for one for my mom some years back after she fell and hit her head and had residual vertigo and issues for months. She lives alone, but very close to family.
Before a year was up and she was better, she cancelled it and told me thanks but I don't need this thing anymore. (90s)

I really can't remember many specifics (Life Alert), only that I had to pick and choose among options, and I didn't need everything they sold, just some of it.
I also recall that mom set it off by accident twice, and the monitoring company did what it promised and started a contact with family both times. (It had not occurred to me to actually test them by setting it off on purpose at least once, and maybe it should have.)