Gotchas Buying Used Tivo?

Are there any gotchas buying a used TiVo? Are any blacklisted like happens with cell phones?

Roamios seem to be cheaper than Bolt. Are they good? I would like it to work OTA for now but maybe with cable card later.

I'm in Charlotte with TWC/Spectrum service now but would like to get rid of it for now.

Thanks,
Larry

Gotchas Buying Used Tivo?