I replace mine when I winterize each fall. It is a bit overkill but the thermostat and gasket kit is only $20. I would rather spend a bit extra each year and be confident that all is good then re-use the thermostat when it was out and easy to replace.
When I winterize I remove the thermostat housing and pour RV Antifreeze into the block until full. I then put in new thermo and gasket and bolt the housing back up. Then in spring, I just put it in the water and start it, nothing to do but connect battery and go. Simple enough