I wouldn't worry about forgetting something UNLESS it was medication, passports or I.D.
Otherwise, you can 'just in case' yourself into packing a trunk. In fact, we're trying to par down what we bring into just one 22" carry-on and a backpack (that's one 22" for my husband and one for myself.) Of course if you have children or special needs that won't work...but for us...less is going to be better!
We learned our lesson while touring China and the Philippines. We HAD to lug our own luggage on and off buses, trains, airplanes, ferries and ships...after awhile we felt like the early pioneers crossing the desert when they started dumping all along the trail the stuff they had once felt they couldn't live without. Boy, so did we. We actually came home with LESS than when we left, including gifts & souvenirs.