How high should the action be on a slide guitar?
Action – 3/16″ above 12th fret E string. This is only a recommendation. It could be higher or lower depending on your skill and how hard you strike the strings. By having your guitar setup for slide, you will now be able to confidently practice your licks and become much more comfortable playing slide guitar.
Are slides bad for your guitar?
If you don't wear the slide on your palm you should be just fine. Playing the guitar normally will wear out the frets much faster than playing slide on it. Just play it and take basic care of it. Life is too short to let a guitar ruin your enjoyment with playing it.