Do you guys mean that you use a towel after a shower, hang it up, then use it again the next day? If so, I've never done that. I use a new one each time.
I change bath towels after about three uses. Hand towels are changed on a daily basis because I use them to wipe counters and/or floors for daily maintence. I change my toothbrush twice a year because that's what Sonicare recommends.