The key to keeping any blade sharp is keep it clean oiled and dry I know the paradox there but most blades need a wee bit of oil and there is a device that will keep your blades for a great while...I have one that I have been using for a month on my disposable and it is sharp as day 1 for $20 it was well worth they try
http://www.asseenontvguys.com/index....ROD&ProdID=517