So part of what I think is going on here is that giving to statistical charity is a slippery slope. There is no one number that it's consistent to give: if I give $10 to fight malaria, one could reasonably ask why I didn't give $100; if I give $100, why not $1000; and if $1000, why not every spare cent I make? Usually when we're on a slippery slope like this, we look for a Schelling point, but there are only two good Schelling points here: zero and every spare cent for the rest of your life. Since most people won't donate every spare cent, they stick to "zero". I first realized this when I thought about why I so liked Giving What We Can's philosophy of donating 10% of what you make; it's a powerful suggestion because it provides some number between 0 and 100 which you can reach and then feel good about yourself.

There's another option which I think may be better for some people (but I don't know because it hasn't been much explored). One can stagger one's donations over time (say, on a quarterly basis) and alter the amount that one gives according to how one feels about donating based on the feeling of past donations. It seems like this may maximize the amount that one gives locally subject to the constraint of avoiding moral burnout.

If one feels uncomfortable with the amount that one is donating because it's interfering with one's lifestyle one can taper off. On the flip side I've found that donating gives the same pleasure that buying something does: a sense of empowerment. Buying a new garment that one realistically isn't going to wear or a book that one realistically isn't going to read feels good, but probably not as good as donating. This is a pressure toward donating more.