I would be interested to hear how HN readers approach charity. I personally am constantly struggling with questions like: once my basic needs are met, how can I possibly justify not giving the rest of my income to life-saving causes? My working theory is a combination of (a) my basic needs are actually quite high when you consider the many potential rainy days for which I must save, (b) I don't know enough to donate…
In any case, don't let indecision paralyse you into inaction. Put some proportion of money aside for charity, start doing research, etc. We're not perfect, it's okay to be a bit selfish, and it's good to want to do better. There's any number of options between a spartan life where you donate most of your money, and donating nothing.