Because I play mostly instrumentals, and don't have the advantage of song identifying lyrics, I try to keep the melody and chords recognizable to the average listener, yet still add some embellishments that a another musician might pick up on.

I very rarely play a song identical to the original recording, but, if there's a recurring motif, or solo, that is essential to the tune, I'll be sure to include it and try to make it as accurate as possible.

To me, the arrangement is like a recipe for a certain dish...some additional ingredients, or juggling the proportions, might improve the outcome, especially for oneself, but it may not be to everyone's taste.

Ian