3 year olds can use regular body wash although toddler and kid body wash is better for 3 year olds or toddlers.
But most 3 year olds and younger kids are okay with using regular body wash.
A 3 year old should be bathed every 2 to 3 days or when they get dirty.
Between baths you can wipe down your 3 year old with a wet washcloth to keep them clean but they should have a bath after 2 to 3 days.
However some 3 year olds may want to take a bath daily and need a bath daily if they get messy or dirty more often which is okay.
Kids need a bath or shower daily when they get sweaty or dirty or when they are going through puberty.
However kids that are not sweating or getting dirty only require a bath every 2 days or so or twice a week but if the kid is dirty or sweating or going through puberty and or has body odor they should bathe daily or shower daily.
Even adults that don't get dirty or sweaty can go a few days between bathing or showering.
However in the summer when you're sweating or the kid is sweating or getting dirty or if you work job such as outdoors where you get dirty then of course you should shower to clean off.
Although once a kid is going through puberty such as over 11 it's recommended that the kid bathes or showers daily as they can produce more body odor during puberty.
After puberty hits, daily showering is essential due to new hormones flowing through the body bringing along unwanted body odor and acne.
Your child should also wash their face twice a day with a gentle noncomedogenic face wash.
By age 4 the child should be able to bathe themselves although you still want to be in the bathroom with them for safety and to ensure they are actually bathing and not just playing and or acting like they are bathing.
When your child can express their needs, understand instructions, and follow simple commands, it is a positive sign that they are ready to take on the responsibility of bathing independently.
By age 4 or 5, children often acquire the language skills necessary to comprehend and execute basic bathing routines.