Historical Reasons

Growing up, I had a pastor who advocated setting an upper limit on your income and donating everything you earned beyond that. I admired the principle of that stance. (It helped that he followed his own advice, living simply even though his books sold many copies.) But when I started making money after college, I learned how easy it was to increase your spending as your income grows.

A few years ago, when I was in the process of converting from being an Evangelical Christian to an agnostic/atheist, I decided that I didn't want a financial incentive to not be a Christian anymore. I wanted to be able to say I was doing it for more pure reasons. I had been giving 10% of my income to my church, so I pledged to continue giving away that much to other causes.

So I've decided that 10% is the bare minimum that I want to give. (And in the past month I finally got around to signing the Giving What We Can pledge.)

Buying Meaning

However, over the course of my lifetime, I hope that I'm able to give away more (if I get really lucky, maybe even signing this other plege). I don't really think of it as giving money away though, I think of it as buying meaning.

I've recently become a fan of the PERMA model of the good life, and I think it's useful to keep in mind when you think about how you spend your money. Paying those medical and tuition bills -- that's going towards maintaining relationships that are important to you, and there is probably a sense of meaning and achievement that come from supporting your family.

Engagement is probably harder to buy, though taking a lower paying job that you found more interesting would fall under this category. Positive emotion can come from traditional material goods, though probably more so memorable experiences like interesting vacations. (For more on how to buy happiness with your money, see: this post).

(It's also worth noting that all of these elements of the good life have diminishing marginal returns, both in terms of how much more of any one of these you can get with more money, and in the sense that if any is neglected, you'll likely get more value from focusing on the neglected element.)

As for me, now that I no longer believe in a higher power with a plan for the world like I did growing up, I've found meaning from supporting the cause of trying to make the future of humanity as bright as possible. That's a big part of what attracted me to Eliezer's writings on this site, and it's why I identify as an Effective Altruist.

I find it very exciting that I'm able to use my resources to support this cause -- if humanity's future is bright, I may have played a part in getting us there. I think it's important to have something larger than yourself to feel connected to, and for me that's it.