Hammer-ons and pull-offs are performed by hitting or pulling the string with the left hand so that right hand does not need to pick. When played well, slurs add a smoothness or legato to the sound. From Vivaldi's Concerto For Lute in D or Pearl Jam's Yellow Ledbetter, slurs are integral to the sound of some of the greatest music written.
Even while writing this article, I know that I'm going to be correcting this common mistake for as long as I teach lessons. Most guitar students have no idea how to play slurs. Among guitarists, slurs are more commonly labeled as one of the following: hammer-ons, pull-offs, and slides.
So many guitarists struggle with slurs! So many things can go wrong until you know what to do. Let's tackle this beast.