I`ll answer that for you, pker124 .... it`s a recurring question .
It`s not possible to give you a definitive answer, because there are just SO many ` local` variables...if you live in a very hot /sunny country, and you spend a lot of time outside, the sun will have an oxidising effect [bleach the color] The type of water you wash it in also ----if it`s heavily chlorinated, this too will have an adverse effect.
In my experience, and I`ve said this many many time, when it comes to system-hair, you MUST remember, you are not dealing with your Bio hair and you have to treat it more gently..... it`s neither necessary nor desirable to shampoo /wash your system-hair frequently .......less is best. The hair gets no lubricating-oils, nor moisture from your scalp, as does your Bio hair, therefore dryness [leading to brittleness/breakage] is your main problem ..anything you can do to counteract that , will pay you back big-time relative to the serviceable-life of the system........usually the hair ` goes` before the base.....
I`ve read so many times of guys who get a system and shampoo it literally every second day and then wonder why it only lasted 8 weeks !!
By all means, mist your hair with water [ preferably bottled water] and simply apply /use a good leave-in conditioner a few times a week...there`s is NO need to use shampoo.....you may of course, rinse the base itself , applying a little shampoo-lather to it and rinsing it off , to remove oils from your scalp....... the conditioner I use is this one ..it`s cheap, leaves no `build-up` of product on the hair, and has a sunscreen in it .... I recommended it to someone a while back and he`s now getting an extra 6 weeks from his systems. It`s the third one down ...the 2nd one is for synthetic hair so don`t get that one ....
http://www.ppi.cc/conditioners_hair_replace.htm I spray on a few darts of it [onto damp hair] and lightly ` style` the hair ...allow to dry naturally..the following day, you can ` re-activate` it by simply misting the air with water .
You could also use a little serum sometimes.... things like waxes/gels/hairsprays, are not such a good idea....they can and do build-up on the system leaving it looking dull and lifeless, so you end up shampooing it all out..this , of course , begins to ` lift` the color, the more you do it ....keep it simple....... so if you follow this simple routine, you could reasonably expect to get a minimum of 3 months and probably a lot more.... I`m wearing a topper now around 3 months and it`s still perfect ..no hair shedding out and no color-fade ....the ` routine ` above is simply all I do /follow.