You'll also find that if you seldom actually wash the unit with shampoo it helps.
Nothing really "builds up" on the hair, unless you put all sorts of styling bunk in it causing buildup.
I very, very seldom actually wash the unit with shampoo.
It does get wet in the shower, as I wash (with shampoo) my existing hair on the sides and in the back, but no shampoo on the top of the unit itself. A little does get on the ends at the sides and back, but that's it.
When I remove the unit (once a week now, though sometimes I do it twice a week) I, again, do not wash it with shampoo. I simply rinse it out very good with cool water in the sink.
That's it.
Washing often causes a small handful of problems, not the least of which is to accelerate the color fading of the unit.
Conditioner is most likely ok, and I use it sometimes.
After I rinse it in cool water, I spray some Nearly Natural on it, add condition, let it sit for the prescribed time, then rinse it out.
Works great.
We could take our clue from many of the women who wear very long hair (my wife being one of them with hair just short of her waist). She Always shampoos her scalp, but seldom washes the rest of the hair. She does condition it.
There is nothing that gets in the rest of the hair, requiring shampoo to remove. The longer part of her hair is like the hair in our units. Nothing (oil from the scalp wise) to keep it from drying out.
I bet if you ask any of the ladies with long, long hair, you'll get a similar answer about their care of it.

Fred (StealthTJ)