Don't spend ingots on anything other then stamina refills and try your luck spins. Just slowly use them up on those, only other thing worth spending on is ingot only events, like when we had Playboy Sasuke/Iruka one, where it cost about 600 ingots to get 2 star Iruka or 3k for Sasuke, which is amazing compared to 5/25 seal scrolls that those ingots would have bought.