Mandatory in MA. As if you had to ask - EVERYTHING is mandatory in MA, whether you agree or NOT!
Just bought a new one last month after realizing my old one was 8 years old .. and the battery was 3!
Had it up to 247 already when I failed to secure a piece of paper in the combustion fan. I was out in the barn, so the stink didn't alert me to a problem. Fell like a rock once I fixed my paper. Definitely got to make a metal slide for that thing. Next year.