Sometimes there are events that hand out so many experience cards that you can have an SSR general go from level 1 to 55 in two days. I use the extra cards from those to level up spare UR and SSR generals on the basis that maybe someday I'll have a use for them. It's been a while since we had such an event, which probably means we're about due. In that vein, just a few days ago, I was thinking we were about due for another inheritance ore event, and now we have one.