Packing is definitely a multi-step process for me! I start by compiling the list of all the things I need to take. Then I put together the first aid/bathroom items (that I don't need the morning of travel) and make sure everything is in the electronics bag. About a week before travel, I put aside all the clothes in the closet. Make sure they are clean and in good repair. I do the same with the shoes (always broken in beforehand). I usually pack the day before, making last minute adjustments as needed.
The mental process starts a few months before. Do I need new shirts, pants, shoes, etc. What kind of jacket might I need, and do I need a lightweight AND a sweater? As the date gets closer, the mental list becomes more focused.
I only travel with carryon luggage plus a daypack. In my daypack (goes by my feet), is one complete change of clothing, my most important bathroom stuff (pills and makeup), electronics bag, and enough room to put my crossbody purse. On my body, I have my heaviest shoes plus my lightweight/sweater. My carryon, which fits in the overhead above my seat, has everything else.
But no, I don't think it matter when you pack your stuff if you're only talking about a day or two. It will still get somewhat wrinkled.