Too much spoiles, too little doth not satisfie.

[Il troppo guasta, il poco non basta.]

James Howell (c. 1594–1666) Welsh historian, writer, aphorist
Paroimiographia [Παροιμιογραφία]: Proverbs, or, Old Sayed Sawes & Adages, “Proverbs in Italian” (1659) [compiler]
    (Source)