On our second popup, we had a hitch ball that was polymer, no grease required. It took a bit of adjustment when we went to the TT and had not only the hitch ball, but two smaller ones for the sway bar. If the sway bar ones aren't lubed they groan, a lot. On my long sessions of being hitched up (NM to OH and reverse), they will groan on the last day or so, more so if I've been driving in the rain. The main hitch ball shows wear from not having a heavy coat of grease, probably also those same long trips, when I stay hitched.