I've seen people going on a ONE WEEK bus tour to Holland and here's what they carry into the check-in line at the airport: a large hardside suitcase on wheels, probably 40-50 pounds, a backpack stuffed to it's fullest extent, say another 25 pounds, and then some kind of cosmetic case, hand bag or carry-all, let's say another 10 pounds. All this for a bus tour of one week's duration in Holland, one of the most modern of European countries!
I'll have a backpack, 20-25 pounds max, and the clothes on my back and I'm set for THREE WEEKS. I'll be first out of the airport, first ready to go in the morning. Porters look at me with disdain and look for fatter fish to cheat out of a large tip. Con artists figure I'm too cheap to bother with. In fact, most of the time I don't look like a tourist at all and that makes for those serendipitous meetings with the locals that can make the whole trip! After you've tried travelling light once, you'll never go back.
I like this line I read once (I think it was in one of Rick Steeve's excellent tour guides): You can't travel heavy, happy, and cheap. Pick two.
First off, if you don't already have one, get a 9" x 22" x 14" carry-on-size bag. I favor the new backpacks this size with the two wheels fitted into the bottom with an extension type handle so it can be pulled along. Even though I'm a reasonably fit 76 years, there's times when I don't feel like carrying 25 pounds around on my back for extended periods. Even on bus tours, you would be surprised at how much walking you may be doing towing and/or toting your luggage along with you. Some cities there may be no parking available at the hotel where the tour has you booked into. Your bus will pull into a parking lot four-five blocks away and then the tour guide will gaily chat you up along the way, hoping to distract you from the distance you have to schlep to the hotel.
Here's a good hint. Pack your luggage, then go for a half-hour walk. Pretend you're walking along the Champs Elysees in Paris on a hot summer afternoon and practice being a tourist. How does it feel? Fully loaded with everything you intend to take, would you enjoy window shopping, shepherding your luggage while you stop for "un 'tit blanc" at that quaint café, battling your way across an intersection between dueling Deux Chevaux? If not then rethink your packing and get rid of the excess.
Meanwhile remember our Paupers' motto. Pack light and Pack smart!
[ Edit: sorry, no promos in the forum please. ]