I’ve been to Cozumel several times over the years. It’s very, very touristy. And touristy usually means more expensive. Probably safer, marginally, than other parts of Mexico. But it’s an island, so traveling anywhere else might be problematic. And healthcare is something you would need to consider.
Ha, ha! Cozumel is a tourist trap. I have been to Cancun and I remember looking at Cozumel from some town to the west. There were 4 cruise ships around Cozumel. You gotta be nuts to retire there. It would be the same as to retire in Banff, Alberta, Canada if the climate was better. Retire in Cozumel and you'll be sorry pretty soon.
Like any place in this world to retire; I would strongly advise to rent there for 1 year before putting any money down for a condo. Buyer beware!
Never been to Cozumel, always avoided it when traveling to Mexico, for the reasons @CarolfromTX explained. I like a lot of places in Mexico, but the places that primarily cater to American tourists are not amongst them.