Old steam traps

I'm a homeowner trying to maintain my 2 pipe steam heating system. I've recently started to install TRVs on my valves, which were completely non-functional (no discs in the valves). Now I'm turning my attention to the steam traps. They are all Hoffman No. 8 traps. Inside, most of them have Barnes and Jones #2168 valves. I have no idea of how old they are or if they work. Some were installed upside down. I don't really have the capability of testing the valves (I don't think). Should I replace them all? Or do these last a long time. They seem to be intact. Thanks for any help.