I hope more people read comments like these and ask themselves: "What warrants these life suggestions? Are they justified? What would make them justified? What alternatives are there?"
Edit: Not talking purely about financially giving back, but also volunteering your time.
You can more easily invest your second million than your first (Because you probably need that (Or at least a portion of that to live)
There's also no significant reason to start earlier (or later), unless you factor in dying as your stopping point, worthwhile causes aren't going anywhere