Traveling: I sometimes have multiple trips lined up, so I put all relevant items for each trip in a seperate plastic folder. Items that are not free yet get replaced by a small piece of paper like "train discount card". That makes sure I do not forget travel specific items.

In general I use a packing list that I regularly update before and after each trip. I also unpack after the trip and check back on the checklist to see if I packed something needed that is not on the list yet. Afterwards I evaluate the items and write that in a seperate column to see over multiple trips if an item is never used (which might indicate I do not need it) or regularly needed but not brought or understocked.

Then I have a box with all the items I mostly use only while travelling. That makes packing these much easier. If my travelrate goes up someday I probably get doubles of most items.

My list also includes actions to before the trip (charge batteries, cut nails) and process goals like having packed a day early and stress free.

The results so far are a much more relaxed time while packing. I am faster and rarely forget anything. I still want to look through the data collected on my last 20+ trips and reorder everything, maybe put in a formular for quantities, or group items that only belong to specific types of trips (long, short, camping, summer, winter).

I found that for me travelling even a crudely done checklist is better than none.