Fast-forward 20 years; retaining my packrat qualities, I began to realize I was overpacking every time I left home for an errand. I also seldom unpacked when I returned home, and I would just "let it ride" whatever was still in the backpack next time I went out.
So I've tightened a discipline of keeping my bags empty while at home. I try to narrow down my mission each day: what is the core task I need to accomplish? Why do I really need to throw this item in the bag? When I return home, I evaluate each item by its usefulness to me. If I didn't even remember it, or think to pull it out, then it's gonna stay at home.
I also try to use smaller bags. I picked up a nice electronics bag at a thrift store, and it fits my phone, keys, bus pass, wallet. So I don't drag around a duffel bag or backpack if I don't need it. Honestly, it's much easier to find something if I don't need to open a dozen zippers. It's easier to ride around on an e-Scooter if I'm not bogged down by 25lbs of kit.
I also try to run drop-off errands more often. I'll take a bag of donations to the thrift store, or some recycling will go out. Then I can have the satisfaction of emptying out my bag, even discarding it and returning home lighter. This contrasts with packrats who will go shopping or picking stuff up every day and they just accumulate more and more stuff at home. You gotta balance that out at some point.