This probably isn't helpful- but at age 26 I still need one. I've always been a messy eater. I think it is because I am easily distracted. When I was 10 my mom paid me a quarter every day that I came home w/ a clean shirt... I think I made two dollars the whole year.
DD is almost 2, and we stopped using bibs many months ago. Not exactly sure when, but like hmbay's ds, my kids rip them right off! I only use one for DS (almost 13 months) if we are having soemthing like spaghetti sauce. Otherwise, we don't use them at all.
Same here, my son is 2 in a few weeks, and I can't even remember the last time he willingly wore one. Maybe he was 13 or 14 months or so? I just invested in a lot of Zout as it wasn't worth the battle.
Don't remember exactly, she was between 12-18 months when she refused to wear bibs. I cut off the bottom of onsies and use those instead. When she wants to eat, she usually asks for a T-shirt. Once in a while she'll refuse that, too, but she isn't too messy anymore.
I guess we're totally in the minority then. DD yanked off her bib for a few weeks a while back but it was just a little phase - we kept making her wear the thing and she just got used to it. She even picks out her own bib now and sets her place at the table. (I guess that's a sign you're getting too old for a bib!) I should stop before she gets embarrased by it at play dates, etc. The other mom's probably all think I'm weird. I think it's saved a lot of nice clothes though. She hasn't had a single shirt stained in the last year that I can remember and she wears a lot of nice white button-downs, etc.
It's been a while since we used a bib! We keep 1 in the kitchen for extremely messy situations (like blackberries - things that really stain and are near impossible to get out), but on a daily basis we never use them.