I largely agree with this though 12-36 months is perhaps a bit high. When I’ve told newcomers to save more and donate less, I’ve usually gotten the response that they really want to donate now because it makes them feel happier and more fulfilled. That’s because they want to do good, but don’t see an opportunity to contribute through ‘direct work’ yet, so giving is their main way to feel useful.
Inasmuch as the goal of giving now is to make someone feel good about themselves and motivated to continue, my objection is weaker. Though perhaps they should try to get that sense of accomplishment some other way while they save.
I think the way I’d phrase advice to someone who’s already excited to get started donating, is some combination of:
a) try to save at least as much as you donate. (As deluks mentioned elsethread, it is totally possible to both donate and save signficantly, so someone who’s already chomping at the bit to donate significantly can probably find the budget for both 10% donations and savings)
b) re total runway time, I think a reasonable plan of action is “get at least 6 months [comfortable] runway, and meanwhile be thinking about your potential longterm plans. A lot of people start out focused on donating but eventually find themselves wishing they had the freedom to start a project, or a join a lower paying job, so at least consider preparing for that sort of possibility.”
On the feeling good about yourself: One way that helped me is to separate the donation money out while saving up for my runway—so I ‘donated’ 10% to a budget in my personal finance spreadsheet, whilst saving about the same percentage in my savings budget—basically committing the money to donations whilst keeping it as a backup for rainy days on my bank account. Once both budgets add up to a 6 month runway (or however long someone thinks they need), you can start donating from the donation budget (+the extra 10% each month). Personally this helped me a lot with the psychological “but I said I would donate 10%” and stopped me from spending the money on other things—whilst being able to take the donation money for runway if I would have needed to do so. The percentages might be too high for some people, but overall I’ve found this way of framing my savings quite useful psychologically.