I put on a 2nd bucket when I'm out for groceries.

Normal day-to-day I have just the left one, and it's mostly empty, although that "empty" gradually gets more and more full as I accumulate junk (receipts, pens/pencils, road-found wrenches, etc). That "mostly empty" includes a couple Park VP-1 patch kits, a Park AWS-1 wrench, a tire lever, and a small plastic container with some disposable plastic grocery bags (in case of a surprise rainstorm, for feet and leather saddle). Daily payload includes wallet, phone, shirt, socks, underwear, food. Jacket, gloves if I'm not wearing them. Jeans, towel if I'm bringing them home to be washed.