I have an Excel spreadsheet that I use, with one tab labeled for "weekend" with a reduced packing list for shorter trips, one labeled "week" with a more comprehensive list for longer trips, and then one labled "shopping" that I add things to ahead of the trip and then print out a couple weeks before to take to the store. I've had the same spreadsheet for many years, and all it takes is a little tweaking here and there and it's ready for the next trip.
I also set it up to print a spot to check off each item as it goes in the suitcase, so I don't have to wonder whether something is packed or not. I learned that one the hard way after having to totally unpack a bag to see if something was in it. It was.