When he looked up he saw some wealthy people putting their offerings into the treasury and he noticed a poor widow putting in two small coins. He said, “I tell you truly, this poor widow put in more than all the rest; for those others have all made offerings from their surplus wealth, but she, from her poverty, has offered her whole livelihood.” (Luke 21:1-4)
Our Lord said nothing about a donation of a set percentage being sufficient or insufficient. God knows whether we are faithful in our use of wealth entrusted to us or not. The question is whether we dare to read ourselves as honestly as God does, with either as much justice or as much mercy. That is a matter for an ongoing conversation with Heaven.
One ought to honor commitments made rather than expecting to satisfy God by betraying the trust someone else had in one to repay what was loaned or contracted. One ought to hold the precept to contribute to the support of the Church. There are some boundaries in place to guide us. Beyond that, the precept is this: “No servant can serve two masters. He will either hate one and love the other, or be devoted to one and despise the other. You cannot serve God and mammon.” (Luke 16:13) Follow that, and you’re likely to do OK.