I've stripped the threads on a quando pretty quickly and the bearings are scapmetal rolled into ball shape, roughly.

How long would it take to save up a new set... it really depends on how you ride. Mine only lasted 5-6monthes before it stripped out and almost got me run over, but I was riding a pretty big gear and brakeless. They'll get you where you need to go, but don't expect much out of them and try not to do any crazy skids.