i keep everything on computer.
i keep detailed records of the pattern i designed, how i designed it, what inspired the design, and how i put the quilt together. this is typically a corel or EQ file.
i also keep a record of how i dyed and painted the fabric. if the quilt started from one of my photos i have the original photo along with all the progressive CG manipulations.
i typically have a scan of the fabric (when hand dyed and painted) and a photo of the quilt.
then i have who purchased the quilt and how much they paid.