Probieren geht über Studieren

Etymology
lit. 'trying goes over studying' or 'trying is better than studying'. Attested since the 19th century. It, along with its earlier form (which is attested since at least 1790), likely emerged as a native and rhyming alternative to, which is a calque of.

Proverb

 * 1) experience is the best teacher; experimentation and hands-on experience is more valuable than theoretizing