I don't use anything on the strings neither. Maybe it's because i don't sweat that much or the sweat isn't very agressive but my strings last like forever. I just change them after a few months for sound reasons. All the string care stuff is just crap imho.
Well, i love cdlc but i bought alot of official dlc. Even some songs i do not like, just for twitch streaming reasons. I think Ubisoft should have realized, RS would be almost dead by now without tons of cdlc. I don't think they try to cut that off. They should use the customsforge stats and release some popular songs instead.