Happiness is finding what you need in your stash! Which means you need to have a stash! Ok - what crafter doesn't have a stash? If you're like me, you inherited some of your grandmother's stash plus accumulated plenty of your own. The key here is to keep the stash under control! Just enough to find what you need, not enough to be <whispering> 'a hoarder'.
So Rule #5 is keep a stash, but just enough. Use what you have and don't hoard it!