Don't forget that you need to be able to take care of yourself but in software that's not too tough as long as your needs are modest. Most of us who have seen or experienced intersectional problems don't have much trouble with that though. As an example, because I've had so many medical issues I've kept a nest egg to take care of myself for a year unemployed, or to spend on surprise medicals bills. If you haven't make sure you make similar considerations based on your own needs.

What I do is donate x dollars per month to some specific charities (namely doctors without borders, direct relief, and transgender law center), and reserve x dollars a month to just give to whatever donation posts I see whole scrolling my tumblr dash.

As others said helping now can get more "moral value" for lack of a better word, than just saving up for a big charity donation, though you could plan for that at the same time. To be honest a lot of organizations prefer consistent monthly donations as it's easier to budget with those than it is to handle a huge some all at once, unless there is an emergency occuring. Same goes for businesses to be honest though who cares about those lol.