You need the biggest pack for a three week trip. Anything over that actually takes less stuff as you do laundry and are usually moving at a more leisurely pace so buying stuff as you go is less of a problem. Pack clothes for just over a week and do laundry weekly. Take toiletries in sizes to cover 3 or 4 weeks (obviously this varies with the specific item) and buy locally to replace when you run out.

Most packs with wheels are a real pain — heavy and uncomfortable to use as a pack. You’ll have many more situations when a backpack is easier/faster/more comfortable than wheeling anything. Wasn’t the cart a pain on your last trip?

Depends on a lot of things (what time of year you’re travelling (if going in summer/fall you need stuff for two seasons), how you’re traveling (train or rental car), what you plan on doing (hanging out on beaches requires less stuff than hiking in the mountains). Personally I use a 40 L. pack and bring only the essentials (Wearing the same shirt 2 days in a row at school/work may raise a few eyeberows…in europe no one will know or care).

Packing light usually means you have to do laundry in your sink/shower every other night, but it’s a small price to pay for not getting a hernia lugging around a 60 L. pack. Smaller pack means I can also usually take it as carry on, thereby avoidng hours waiting for my stuff on the baggage carousel.

Try here!

Sounds to me like you didn’t use the waist belt properly. It shouldn’t be that bad. Anyway, you can get a smaller one if you want to. I assume you’re not going alone so you and your friends can pay to have your washing done. Throw what you want washed into one load and you each spend a couple of dollars weekly. This way you can site see and pick up your stuff later.

If you take some old clothes that you don’t like, you can give/sell/trade at thrift stores. (Off the wall idea.)

If you do decide to invest in a smaller one, the important thing is to get one with openings on either end and/or in the middle so you don’t have to dig too much to get what you want.

The next important thing is to get a good deal on one. If you don’t think you’ll be travellng much more, just try to borrow one.

If you’re country hopping, traveling by trains, staying in hotels, I would recommend getting a rolling suitcase for the convenience it offers. You don’t want to return from your trip with a serious back problem because of lugging around a heavy rucksack everywhere you go. Check out this Expedition duffle (http://www.briggs-riley.com/category/productDetail.aspx?id=Expedition-28-Rolling-Duffle_BUD128) from Briggs & Riley’s BRX collection. It’s got plenty of space and looks sturdy enough to withstand any kind of travel abuse. The assurance stems from BR’s unconditional lifetime warranty offer on their entire luggage collection!

Try pulling a suitcase with rollers down a cobblestone street.

Suitcases are for old ladies.

Get a good backpack with a good waist belt and some sort of internal frame. A well adjusted and properly packed backpack will goive you no troubles

Take the “oldlady” test. Load up all your gear in your wheeled suitcase. Walk around the block twice (assuming a “normal” European block with rough sidewalks, cobblestones, areas with no sidewalks, no curb cuts) then immediately walk up two flights of stairs.

SPAM!!

This person has has no idea what they’re posting. If you want actual back issues, get this over priced piece luggage/crap. A good backpack with a proper fitted belt is the best friend you can have for budget travel.

How can a rolling suitcase be recommended for trains?

Never more than 40L, unless you are going to the North Pole in the Winter. That will hold, 2 prs long pants, 4 prs shorts, 4 T-shirts, 4 pairs socks, 5 prs skivies, bathing suit, + 1 sweater/fleece, light weight raincoat, a razor and toothbrush, easily, plus a ton of other stuff AND it will be pretty heavy. Wash some clothes once a week.