I wet the bed until puberty, and my brother sucked his thumb until college (assuming he stopped then).
What did you do, and when (if ever) did you stop? And those of you with kids: have any of your kids inherited your bad habits?
I sucked my thumb until I was about eight. Yes, it did fuck up my teeth (though they were fucked anyway: weak enamel and a narrow jaw - thanks, mother. At least I actually had enamel, unlike my uncle).
I bit my nails. I can’t remember when I stopped, but I have a horrible feeling I was well old enough to know better. Now the thought is revolting to me. Ugh. Soggy, gnawed fingers. That also damaged my teeth; I have a chipped/worn corner to one of my front lower teeth, because that’s the one I always bit onto. They never tell you about that when they’re trying to make you stop!
I may have had pica when I was a kid, but I used to eat paper, pencil wood, and erasers. All of the books I owned when I was younger would end up with the corners torn from the pages. All of my pencils looked like termites had chewed on them.
It all stopped when I got older and went to college, for which there might be several reasons. Before I went to college, I lived the majority of my life in Taiwan and Indonesia. There is a good possibility I was lacking various nutrients in my diet and my body tried to get those nutrients from paper and wood.
It might also be that the paper in my books, in particular, had a higher pulp content than paper found in the U.S. I don’t have the urge to eat paper any more, although if I eat a lollipop, I will sometimes eat the paper stick, as well.
I sucked on my clothing. Lots of dresses with ratty collars from that era. Stopped when I was old enough to know better - probably 9.
I used to love sniffing things like permanent markers, certain kinds of glue, or those mimeograph sheets we sometime got in grade school in lieu of photocopies.
I was a dare devil and accident prone. Bad combination. I got stitches numerous times. The first time I was showing my younger sister how to ride her tricycle backwards and went down a fight of cement stairs at 4. I had to get stitches in my head. Then I rode my bike down hurricane hill no hands, no feet and then my tire hit a rock and over the handlebars I went and got a concussion. I almost drowned, fell in a rose bush, jumped over a jagged stump and ripped my lower leg open, more stitches, heat stroke, a boating accident, Dumped a dirt bike and got more stitches, broke my toe. I was lucky my Mom was an RN and the ER was just down the street.
Nail biting, and I still do that.:o Up untill eighteen years old, my fingernails often looked bad as well, but nowadays my fingers look presentable.
But I still tear off and prod my toenails, often past bleeding point. At least I can get my feet presentable in sandal- time in summer, now that I found a manicurist who also does acrylic nails on my big toes.
I had trichotillomania, had a comforter, and bit my nails.
After crying, I’d wait a while for the salt to dry on my eyelashes, then I’d scrape it off with my fingernails by pinching the eyelash between my thumbnail and the pad of my index finger like I was going to pull it out, only gently enough that it usually wouldn’t. Instead I’d have this perfect salt crust left over on my index finger. It was fascinating and incredibly satisfying. Unfortunately, I never grew out of it. Yeah, it’s weird and probably a bit gross, but it could be worse, I suppose.
I also had a blankie. I wasn’t really attached to the blanket, but I was attached to the smell. I grew out of it by about 10 years old, but for the longest time, I couldn’t sleep without taking a huge whiff of my blanket. I still love that smell. My baby daughter’s breath smells like that - vaguely sweet and salty - so I’m constantly inhaling as deeply as possible when I kiss her.
I sucked my thumb until I was eight. Then of course I had braces. My mom did everything to get me to quit, but I just did not care–it must have been infuriating.
I also picked at my nails, and still do somewhat. I’m getting better though. I know it’s a horrifying habit! :o
Um…nosepicking. Which I never been able to stop.
Hey, at least I never chewed on my nails!
My mom said I was a “picker.” I picked at stuff when I was bored.
There was a bead of black caulk around the back window of one (or more) of our cars growing up. I would silently sit there with my hand up in the air, picking away at it, getting my hands all black.
I’m sure I picked at other stuff too.
I gave it all up when I started smoking instead 
I also wet the bed. In the past tense - I gave that up too 
I was lazy, same as now.
Constantly licking my lips. It lead to a childhood full of painfully chapped lips, but it was an ingrained habit that I just couldn’t seem to shake until I hit 10 years old or so.
Sucked my thumb until about five. Slept with a blanket until I was about. . .older than I’d like to admit. 18. I didn’t take it with to collage. It’s not really a comfort thing so much as a being-used-to-having-something-in-the-crook-of-my-elbow thing. Now I have a stuffed wombat and an UglyDoll, so it’s okay.
I also chewed pen caps. God, did I chew pen caps. The tops of pens, too. That last was the bad part; sometimes the ink would come up, and it was absolutely disgusting. I stopped sometime in college. Mostly. Sometimes I’ll catch myself about to do it or starting to do it at work. But I really don’t anymore; before, every single pen cap was mangled and disgusting.
Bit my nails. I still do somewhat, but they are long enough not to look bitten. I overate and was a fat kid. Now I overeat and am a fat 73 year old. Not gross (6’0", 235).
I chewed on pen caps and sometimes the pens. This ended about the time of my first crown.