Vaporstat L408J 1009 life cycle?

A little less than 5 years ago I replaced the Pressuretrol on my home single-pipe system with a Vaporstat L408J 1009. It was mounted on an upper port of a Burnham boiler, sharing a siphon loop with the pressure gauge. (The boiler was installed in 1994, before we moved in.) I recently noticed that the cutout pressure was 3.8 lbs, as measured on the gauge, rather than the set 14oz. Cut-in was still 6 oz, as expected. Replaced the Vaporstat, and gauge shows expected cut-in and cut-out.

I replace the thermocouple for the pilot light every two years, after two 'no heat' experiences; one at a very inconvenient time. Should I be planning to replace the Vaporstat every 5 or 4 years in a similar fashion?

Thanks,

Ken