Oh I see. You have the manual that states how weapon parts should and shouldn't be used. Yes, start at 0. Then you can see how difficult it is to upgrade anything at all. Between experimenting with rolls purchased on gunsmith weapons, upgrading new exotic guns from quests, infusing guns to use in trials, infusing guns to use in the HM raid and several other applications not including exchanging parts for faction rep it leaves you absolutely bone dry. I started TTK with around 300 parts. Experimenting with the new meta, the Gunsmith weapons every week, purchasing a few exotic primaries from the kiosk, chasing every exotic quest from the NTTE and First Curse, has blown out my weapon parts. I had to dismantle nearly all my old Y1 weapons and several 295+ weapons just to get 1 or 2 upgrades. It isn't a matter of whether or not I play enough. I've put in around 500 hours after upgrading to XB1 in the last month or so. I've done just about everything there is to do. I have 4710 grimoire (NOT THE HIGHEST, I KNOW) so it isn't like I'm some slouch. So what's the manual say? Or are you a Bungie Developer and know exactly how we were supposed to use our weapon parts despite putting out an expansion with the biggest weapon armory to date? Are we supposed to try out all those weapons or just stick to 1 weapon and dream about the things we can't have?