We have done BBB 3 times.
The first time, her hair was SOLID and stayed for 5 days, through park days and naps....no swimming (it was December) and was pretty hard to wash out.
We went a year after that and pretty much same thing except she wanted it taken down after the 4th day...again, kind of hard to wash out.
We went for the 3rd time back in October of last year (10 months after the 2nd trip) and her hair wasn't quite as solid, but it stayed for 3 days, but started look frizzy at the end of the 4th, so we jumped in the shower, and with ONLY water, it rinsed out of her hair and left it soft, like it was conditioner.
Not sure if they are using different product or not, but it sure seemed like it!
I loved it!