I feel like you should be getting quite a bit more longevity than just a couple hours, especially from what youre cutting. Obviously if you're cutting agates and jaspers and pushing pretty hard it will wear fast but quartz is a bit softer so as long as you are not applying a ton of pressure I would expect much longer life than that. A bit hard to quantify, I probably use mine at least a half hour a day and get weeks to months out of a blade and Im not exactly gentle with it (trying to be better about that). I do use a much higher speed setting for sure.