These questions feel to me like they come from a very different perspective, so I want to try and explain how I think about it. If I continue on my current path, perhaps over the next 40 years I might manage to donate $10M. There's a sense, then, in which I have a target of $10M. If through some unrealistically good fortune my 0.34% of Wave stock options turned into $50M, however, I wouldn't donate $10M and then devote myself to leisure.

The level of need in the world is enormous, far bigger than my personal efforts can address. The poorest billion people need a marginal dollar far more than I do; no one should be dying of malaria; our society's ability to handle a pandemic is terrifyingly bad; we are putting much less effort than we should be into making sure humanity doesn't go extinct.

Now I'm not going to sell all my possessions and live as cheaply as possible, but I am going to be thoughtful about balancing costs to myself against benefits to others and making good altruistic tradeoffs. The more money I have, the larger a portion I can give while continuing to spend money on myself in ways that make me happy.

Considered this way, responding to receiving $50M by decreasing the percentage I gave would be exactly backwards.