If you can pack everything you need for a long trip in carry-on luggage, go for it, but if you're flying abroad, keep in mind that carry-on size restrictions are often more frequently enforced on international carriers. Budget airlines in Europe are especially known for this, says Rick Steves.
Image from Lisa.
Beyond having different size and weight restrictions for carry-on luggage than many domestic carriers, you may also have to keep enforcement in mind when flying international airlines. Travel expert Rick Steves explains:
Be aware that some airlines, especially many of Europe's budget carriers, have carry-on size limits that are smaller — and usually much more strictly enforced — than what we're used to in the US (where 14" x 22" x 9" is the general standard). They may also have more stringent weight restrictions for carry-ons.
It's not always the case that you'll have a problem, and you shouldn't expect someone to measure and weigh your bags at the gate, but if you lug or wheel an unusually large or bulky bag to the gate, someone may stop you and force you to gate check it — for a fee, of course. Head to your airline's site to find out what their specific carry-on restrictions are.
Tips for Choosing the Best Travel Bag [Rick Steves]