Even non-beginners 
@stitch, I agree with all of this. I have the original BPM as a target, mostly as a personal challenge, but I generally end up at a speed that I like and sounds good to me. Sometimes it matches the original speed, sometimes it’s different (could even be faster). I play only instrumental pieces, so I have a lot of freedom on the tempo.
@jjw @stitch It has little to do with ability. I can play the same picking patterns with different fretting patterns faster and play other songs that are just as complex at twice the speed. This is a mind trick. If you become accustomed to playing something slowly, it makes it difficult to play it at a faster speed. Playing with others or recording with a backing track doesn’t work well at the wrong speed.