I use a checklist for the external and pre-/post-start stuff but have tried to commit to memory the inflight & emergency stuff.
I just wonder if/when I every try a retractable, I'll sail through the "Brakes off, undercarriage down..." bit on downwind and not actually do anything, just like I do in my 172.
I'll always keep a checklist with me and annotate it with my own personal bits.