After some experimentation and investigation, I've come to the conclusion that it takes a really long time for any grit or lint to work its way into the pivot itself, due to the gap between the blade and washers being so tight. However, the detent ball glides across the exposed part of the blade and can get gritty, sticky, washed clean of lube, and result in a sticky or gritty feeling knife. I feel the key to a smooth sebenza has more to do with the detent ball and track being clean and lightly lubed, than the pivot itself. If my knife starts to feel sticky, I clean the detent track without taking the knife apart, using some folded over paper towel, and then apply a tiny bit of grease with a toothpick. Voila.....smooth knife again.
This works for me, and might be worth a try yourself. Just saves a bunch of unnecessary dissasembly after you cut an orange etc, and your pivot seems suddenly crappy.