> we suggest income doesn't have much effect on happiness after $40k, or $60k if you live somewhere expensive, and plus $20k if you have a child
Huh? Are you guys based in the United States? Did you pull that number out of your ass? Do you know the difference between "diminishing returns" and "doesn't have much effect"? In the vast majority of the United States where the median income is $40k and above, it won't actually be enough to meet what most people on HN would consider basic needs - housing, healthcare, food and some savings for retirement.
> First, save enough that you could live for 12+ months with no income.
An impossible task for the majority of Americans. Again, I'm not sure where you are based, so this is forgivable.
> Then save a decent fraction of your income to maintain this level of income in retirement
You're telling people who are earning $40k to save $6k and meet their living expenses on $34k. While that may be possible in some areas, these areas tend to be the ones where $40k jobs are at a premium and are not available for the majority of the people there. See my first comment.
> Always donate a small amount (say several percent) to keep in the habit of giving and learn more about charities.
Donating money while earning below median income nationwide is an advice so terribly inane, it doesn't warrant a response. You're always better spending that amount (minus the marginal tax rate) on yourself or your family, especially at the levels of income you're suggesting.
> After you're meeting your saving and consumption targets, you can donate most of the remainder.
Which for most Americans would be never. You have to step out of your bubble and look at some BLS numbers if you want to give economic advice.