I don’t have kids, but I love the trick-or-treaters, and my absolute favorites are the babies that are carried by the parents or in a stroller. Really, the younger the better cuz they are just so darned cute in their costumes and they often say very cute things. IMHO, 18 months is old enough to go.
I make up Halloween bags with candy and toys, and I make a few age-appropriate bags for the very young ones; there’s candy, but I assume the parents will eat it.
Mine’s born in December. I didn’t take him at not-quite-one, we didn’t really have the neighborhood to go carting a baby around in. It’s nice enough, but all “established”, meaning old people with dogs. And not enough streetlights. The next year, at not-quite-two, he went as Bam Bam (which was his nickname). It was insanely adorable. We went to a local mall which had tons of trick or treaters. It was great because it was well lit, and easy terrain for a new walker. The next year he was supposed to be an adorable lion, but at the last minute refused to wear the head piece. Bam Bam again! Boy was I lucky that costume still fit. We did the mall again. I second the poster who said they eventually implode. My tips would be, decide your route in advance. Start furthest and then work your way back home to make it easy when the eventual implosion happens. Eat dinner first. Have lots of flashlights and glow sticks and a plan if you get separated (more for older ones that you will actually be letting go of). Think about camouflaging normal sneakers instead of using what can become uncomfortable halloween footwear. Plan long sleeves or jacket into the costume as well as removable layers (tights etc) in case it gets hot. If you’re potty training, you might want to think about which neighbors have a bathroom you won’t mind asking to use. Not to mention the ability to de-costume. Mine had to pee behind a tree at 3! Luckily he was Frankenstein and the costume was easily removable.
Enjoy! I love Halloween. I have made Littledorky’s costume every year except one when he was superman, and he’s been Bam Bam twice, then Frankenstein, Sonic the Hedgehog, Superman, Astroboy, and last year, the cone-headed zombie from Plants vs. Zombies. Only like 2 people recognized him.
This year, he was all set to be the Flying Spaghetti Monster but has now decided he wants a store bought, “regular skeleton” costume. I’m letting him have that but I am totally bummed, as making the costumes has always been one of very my favorite things.
I’ll echo the other posters who enjoy having parents bringing their babies around. Candy must be given too; that’s part of the ritual. I don’t care who eats it.
I don’t think I was taken out until I could walk, but I don’t remember back that far.
We didn’t live in a kid-friendly neighborhood for my son’s first Halloween - and we were busy packing to move right then anyway - so we waited until he was about 18 months. His name is Jack, so I dressed him up as the kid on the Cracker Jack box.
We didn’t take my daughter out her first Halloween, since she was only four months old and cranky. I did make her a pair of kitty ears and drew a nose and whiskers on her to appease her big brother, Captain America. Apparently I didn’t take pictures the first year she went out. Oops.
At 8 months and 16 moths we dressed our daughter up and visited Grandparents and a few select friends and she “trick or treated” with them. At 3 she started doing the tour of the neighborhood.
Funny story, her first time going trick or treating she and mom went out for the first round and I stayed to man the dorr. 5 mins later they came back in and thought “oh God. what went wrong?”. It tuned out that our next door neighbor, the Hershey’s sales manager, had filled her bucket to the rim with full sized candy bars! Daddy made out like a bandit that year. 
I still miss those neighbors.
Five months. Obviously, she wasn’t walking on her own, and had no clue what was going on - but it was fun for the rest of us!
If they existed for Halloween, they got (and still get) dressed up for Halloween 
When they were infants or pre-walkers, my kids were dressed up as peapods or pumpkins (or in one case, in a “Baby Bjorn” front-carrier while mama wore a kangaroo costume - pre-dating my use of digital cameras though).
My son was 18 months his first time. He spent his first trick or treat with me on the porch handing out candy. The following year he got dressed up and went around with another 18 month old friend of his. I’m not sure they even got to the end of the street before they got tired of it.
Awww, too cute!
I’m guessing 20 months here
I think a Zombie Pumpkin would have punkin guts, maybe died red (although braaiiinnzzzz aren’t red).
Cute pics. I’m sorry my great-nephew is allergic to everything. He probably will never get to trick-or-treat door to door, unless his mom sneaks ahead and gives the houses appropriate food. Broccoli isn’t much fun to get on Halloween anyway. 
StG
At 10 months, we just had an in-house baby party, with the Sprout dressed as a frog. At 22 months, she wore her cheetah costume to go Trick-or-Treating, which took forever to work up the courage to put on but once she’d worn it she loved it. At almost three, she begged for months to be a stick bug, and so she wore the stick bug costume I made, the picture of which is the main reason I’m posting here, because c’mon, that costume rocks. This year I’m working on a dragon costume. I figure the earlier the better.
18 months. She made her own costume (we just cut arm holes and a head hole in a paper bag and she scribbled on it). No going up to doors or candy, but she loved walking around and seeing th epumpkins and the other costumes. It is a big holiday for kids and a really fun unusual one with going out at night and seeing the neighborhood in a different way. So I’d encourage you to take your kid out for a bit even sans costume or knocking on doors.
Pity kids don’t soap windows any more.
We liked dressing up ourselves, so the little one was an Ewok at the age of 3 1/2 months. Not really trick or treating, but some visits to family.
As old as she could walk.
She had the best line a few years ago. She happened to get up to a door at the same time as two other children, so they knocked together and yelled “trick or treat!” in unison.
“Oh, and what are you tonight?” said the old lady who answered the door.
“I’m a witch!” said a little girl.
“I’m Spider-Man!” said a little boy.
“I’m here for the treats,” said my daughter.
For my oldest, we first took him at age 2. For my younger, we took her out the first halloween after her birth.
