How often should you really wash your hair?

We asked three experts for the low-down on shampooing frequency.

Lathering up your locks with shampoo and following (maybe) with conditioner is the most basic hair care step, but it can still be tricky to work out how often to wash your hair to keep it in optimal condition.

For most people, leave your hair unwashed for too long and it gets limp and greasy. Shampoo too often and you can end up with frizzy, dry strands. So where's the happy medium?