I’ve run a couple single-user Pleroma and Akkoma instances for 1 to 3 years each, one of them with a lot of follows in both directions and plenty of multimedia, and it worked fine on hardware 6 generations old on a crappy Comcast plan proxied thru a $4/mo VPS.

Other platform software (Mastodon especially) consumes vastly more compute resources than the Pleroma family. I haven’t tried self-hosting Lemmy yet. YMMV.