Every day.
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
Only residue-free shampoo should be used on dreadlocks.
You should not shampoo any bunnies no matter how old they are.
Who carries shampoo around? No one. So no, they shouldn't.Yes, shampoo always comes in handy!
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.
Most of the time guinea pigs don't have an odour as long as you clean their cage often. If they are still stinky, you can always give them a bath. If you want to give then a bath you should either use bunny, kitten or ferret shampoo, dog shampoo is too strong and natural shampoo is the best for them.