Rav Ezriel Tauber used to give 80 percent of his earnings to tzadaka. In his life he gave many tens of MILLIONS of dollars away.
He was asked that Chazal say that one may not give more than a fifth to tzdaka? He answered that he will manage with that "aveirah".
He was being humble. In fact, there are numerous "heterim" to give more than a fifth so he did.
One doesn't have to be a Tzadik to give a lot of money to tzdaka. All one has to have is a little bit of heart and notice the countless religious Jews who life in constant-relentless-unending-debt. It should bother one so much that the only way he can sleep at night is if he does all he can to help.
We should all merit to be from the givers and not the takers.
