Most Pilot Operating handbooks will have a detailed list of items to be checked under a main header of "Normal Procedures" or something similar and will have the list sub headed providing some additional information e.g. Left Wing Trailing edge (heading) and (item) Aileron- Check security and full and free movement, whereas a checklist in the cockpit is usually on a card. The aileron will be on 2 checklists, one being the preflight walk around inspection and the other on the card in the cockpit (full & free meovement).
The full POH checklist can run in to several pages whereas the card in the cockpit is a simple memory jogger to make sure each check is carried out.
If you think you have everything committed to memory, think again. You will forget someting sooner or later. Our aircraft may be simple but we still forget things and adhering to a checklist is the best way help prevent this.