I never plan out an entire solo, but I do work on licks in the practice room. While I don't necessarily have the intention of playing them verbatim, sometimes I do. I just purchased the Charlie Parker Omnibook, which has transcription of most of his solos (I would've done it myself, but I mostly transcribe easier players.) I'm stealing lots of his licks, but only maybe 2-4 bar phrases, and i'm trying to tack them onto my own licks, to create long flowing lines that I can use. I think it's a good step towards getting me better at playing my own stuff in his style. I already find myself creating better licks on my own from having looked at his so closely.