I take a picture of every quilt, handbag, wall hanging, etc pretty much any and everything I make and store it by year in my computer. I have a folder labeled "Completed Craft Projects" with sub folders for each year, photos dated and labeled as to what and who for. It is so easy to take a picture either with a camera or smartphone. I sometimes take pictures as I work on a project or to check the layout of blocks. That is the extent of my record keeping, unless it is something I have made up myself or altered a pattern so much that it needed an explanation in case I wanted to do it again. In those cases I write up a word document and save that.
I do back up the folders to an external hard drive as it is my only record. Details as to fabric, start stop dates, supplies, etc are lost forever, but I have never really needed those details anyway. I am just pleased if I do remember to take the picture of completed project!!