Have enough sense to know, ahead of time, when your skills will not extend to wallpapering.
Wisdom And Prudence
by Friedrich von Schiller
Wouldst thou, my friend, mount up to the highest summit of wisdom,
Be not deterred by the fear, prudence thy course may deride
That shortsighted one sees but the bank that from thee is flying,
Not the one which ere long thou wilt attain with bold flight.