Jewish tradition says to give from 10%-20%. I have been giving 20% for the last few years and that is exactly how it works. The first thing I do when receiving my paycheck is putting 1/5 into a separate account which must be used for charity. It is anyhow all accounted for with monthly donations to various charities. I find it to be incredibly empowering personally, as I can support the charities I choose without agonizing over each donation. I already made that commitment a few years ago.

WRT income, I am thankfully able to afford my lifestyle, but I currently earn 5 digits a year and always have (I am still young). I don't regret a penny I gave.