I've been saving my life and bond crystals along with my sun medals (stopped buying rainbow skillblooms around half a year ago, started only buying the cheapest of each second affection material when the supplies reset in the bond crystal shop (13 per regular amber and the like), etc) which generally leaves me with more than enough of each resource when Something Important is released.

Now that the normal 80 stamina bonus stage can drop 10 life crystals I sometimes try my luck with it if I have nothing better to spend the stamina on.