Is it unhealthy to not wear underwear at all?

It is very healthy not to wear underwear, particularly if you suffer with thrush etc. as it keeps the area dry and cool.

Many women (and men) don't wear underwear at all. If you wear very short skirts then it is too alright. It does mean more laundry and/or dry cleaning as going 'commando'is very sexy and you tend to lubricate more with no panties to soak it up. Going commando lets the air blow up into your vagina and therefore it cleans it out!