It`s not possible to have more hair added into a system once it sheds..particluarly on Polyurethane bases, as the hair is injected by machine into them,..... lace bases can have a `patch`job done on them, but for the cost, it`s more economical to simply replace the system once shedding becomes an issue... shedding should really only begin towards the end of the `life`of a system.... it`s not worth having new hair added as the new hair will also look `fresh` and different to the existing/older hair . These Toplace systems are affordable and therefore the best thing is to replace a system once/if shedding starts. Some wearers get maybe 3 months wear out of one, others can and get over 6 months...depends on many `local`factors such as your care routine, your lifestyle [swimming in chlorinated water is hard on any hair] so it`s no possible to give a concrete estimate of how long a particular system will last, no more than how an individual`s body physiology will react to/with various bonding products and substances...it`s a case of individual `trial`to find what works best for you.I also think the reason there are mostly men on here is simply because men suffer baldness far more than women and usually [ but not always] women wear out of choice--particularly women of Afro-extraction as it seems to be part of their normal fashion to do so, even if they have pretty good growing hair.. I`ve seen many videos on Youtube of them bonding/cleaning their systems--it seems to be a `normal`part of their `routine`for many of them,whereas caucasian women don`t seem to be as into it at all, apart from needing a system in the unfortunate event of having to undergo Chemo therapy with the resultant hairloss.....just my `observations`..... Paul.