To clean a toddler girls private area you should wipe front to back to prevent spread of bacteria into the girls vagina which can lead to infections.
Especially with a poop diaper you don't want to wipe that poop to the front because it can get into the vagina and lead to infections because the poop contains bacteria.
To clean a toddler boys private area you should wipe the private area from front to back.
However with boys you can wipe the poop first from the back and then clean the front again with some baby wipes.
Although with pee it does not really matter whether you wipe front to back or back to front with boys.
To clean your baby's genitals, you can use warm water and a cotton ball.
If you want to, you could add a small amount of mild cleanser with a built-in moisturizer to the water.
Nappy free time or diaper free time should be at least 30 minutes a day although even an hour a day can be good.
Giving your baby and toddler nappy free time or diaper free time can help prevent diaper rash as it allows their skin to have some air to it for awhile.
Being in a diaper all day can prevent the skin from breathing properly which leads to diaper rash so it's good to allow the baby or toddler some diaper free time at least 30 minutes a day.
Babies do need to be wiped after pee as pee can linger on the skin.
If the baby is wearing disposable diapers then the pee is not as likely to be on the babies skin but even small amounts can be on the skin.
I always wiped my babies skin with a wipe even after pee to clean them up.
Babies can wear diapers for 12 hours or all the time.
However a baby should not wear the same diaper for 12 hours before changing unless it's just at night.
In the daytime hours the baby should be changed as needed such as every 2 to 3 hours depending on the babies age and how often they pee and poop.
Poop diapers should be changed as soon as you notice.
Pee diapers should be changed when full or every 2 to 3 hours.
Older babies and toddlers can usually go 3 to 4 hours between diaper changes in the day.
As babies get older they tend to hold it in longer and pee less often so they don't need a diaper change as often.
Newborns go through more diapers per day than older babies and toddlers.
As the toddler gets older they use less diapers and after age 18 months to 2 years old a toddler may only need 4 diapers per day.
Although diapers say they can hold up to 12 hours that is mostly meant for the night and not in the day.
A child should have their diaper changed way before 12 hours as they could get rashes and infections during the day.
Toddlers and babies tend to pee more in the day and would likely fill the diaper up with pee before 12 hours have passed.
So make sure to change the diaper in the day at least every 2 to 3 hours when it gets full.