With regard to donations always expect the most from prudent people, who keep their own accounts.

This is attributed to Addison in The Columbia Dictionary of Quotations (1993) with a citation of "Economy and Benevolence" in Interesting Anecdotes, Memoirs, Allegories, Essays, and Poetical Fragments (1794) but that was a publication of a contemporary "Mr. Addison" in several volumes, and not the poet. Vol. III of that publication (in 1796), on page 205, does contain these lines, but as part of an anonymous ancecdote.