I try to apply the hybrid philosophy of: "work hard, make money, give what you can afford to give today, give yourself a near-mode incentive to make more money, and create savings for the future".

The savings one is a big one you didn't mention. I feel like my future self has a high chance to smack me if I commit too much money now. It seems like the places I would give today can benefit more now from my donation than in the future, but I may find better places to spend the money or give it away in the future. Hence the hybrid.