Every other day
It depends on the individual. People with very dry hair do not need to shampoo as often, while people with very oily hair should shampoo more often.
everyday when you shower right after you put shampoo in it
Everyone is different. It depends on how much oil you produce and how long your hair is.
Yes. Boxes often say to just use water but you should really be using shampoo also as otherwise your hair can become more damaged and dry.
Shampoo should not be flammable.
Depending on the shampoo you are using... you should change your shampoo every 2 weeks or so
It depends on the animal
In real life, only as often as the horse needs to stay healthy and clean. Too much bathing can cause skin problems such as itching and dandruff.
If is safe to shampoo daily, as long as you are not using a weekly clarifier that will strip your hair. I wouldn't recommend much more than this but unless your hair is extremely fragile, it will not be hurt from washing it more.
You should not shampoo any bunnies no matter how old they are.
Only residue-free shampoo should be used on dreadlocks.