In order not to cause unnecessary holes in the apartment I use for years Tesa Powerstrip hook. The hold bombproof, even with wet - it towels or a bathrobe - so heavy. The "trick" is, of course, the really correct installation: underground degrease (best with window-cleaning spray), wipe dry, stick adhesive strip, press it for 10 seconds, holding plate it stick, also press for 10 seconds or attach hooks - takes all in all more than 5 minutes - and holds for the next few years. Several hooks sticking so in my bathroom for at least 5 years, a hook I have last year (ie after 4 years) need to lose weight, was easily detached from the wall and stuck with a new adhesive strip at another location - holds! I can Tesa PowerStrip Hook really recommend it (in all other sizes and Poster trips for wallpapered walls).
