A child should be potty trained and out of diapers in the day by age 2 to 4 years old.
Most kids are potty trained and out of diapers in the day at age 18 months old but some children may not be ready to potty train until age 2 years or 3 years old.
In rare cases like my own son it may take until 4 years old before the child goes potty and stops wearing diapers in the day.
My oldest son when was 4 just decided he was gonna use the potty and he ran to the toilet and then removed the diaper and used the toilet and refused to put another diaper on.
I then put him in underwear and he hasn't had any accidents.
If the child has no incontinence issues, disabilities etc then the child should be out of diapers in the day by age 4 at the latest.
But if the child does have health issues and needs to wear diapers in the day or night then they are never too old to wear diapers.
Diapers are made for all ages and they are just an absorbent type of underwear and if you need the diapers you need them.
Nobody is ever too old to wear a diaper if they need to wear diapers.
Diapers are made for all ages and if a person needs to wear diapers whether they are 1 year old or 100 years old they should wear the diaper.
Although babies and toddlers are mostly the ones wearing diapers because they cannot or won't use the toilet and they need the diapers to catch the pee and poop it's okay for older kids, teens and adults to wear diapers as well.
Some kids as well as teens and adults are disabled and cannot physically use the toilet and need diapers full time and that's okay.
Or some kids, toddlers, adults, teens may have bed wetting issues or be urinary or fecal incontinent and need diapers either in the day or night.
I have an 8 year old nephew that needs diapers all the time because while he can physically use the toilet he is urinary incontinent from birth.
So he has to wear diapers or he will end up in wet pants.
The 8 year old nephew is skinny enough he can easily fit into a Pampers Cruisers size 7 diaper.
Youth diapers and adult diapers are too big for him and with his heavy wetting other cheaper diapers don't work for him.
We told him he's not a baby because he wears the baby diapers and he understands that.
He doesn't seem to be embarrassed either by wearing the diaper and in the summertime I go over to his house and he's sitting there on the floor or couch and wearing just the Pampers Cruisers Size 7 diaper and either a shirt and socks or just the diaper.
To me he's still got a baby face and looks cute and I did snap a picture of him like that with his permission but I'm not sharing it to everyone out of respect to him.
Eventually he'll need to wear youth or adult diapers as he gets bigger but for now he will fit into and wear the pampers diapers which are very absorbent.
The 8 year old boy has accepted his need to wear diapers and seems no longer ashamed of it.