I've made up my mind to only travel with a carry-on from now on. I was only vindicated in my opinion the other day, when an airline lost my mother's luggage. These days, limiting yourself to a carry-on means you save money and more importantly, a ton of hassle. Gone is the need to wait for your luggage after you've arrived. Gone too is the stress and possibility of your baggage being lost or having been sent to the wrong place. I would also add that you probably save a fair bit of wear and tear, not to mention that you will be rather more mobile with smaller luggage.
But you sometimes really do need to pack heavy. In that case, your carry-on gives a good amount of extra storage. Either way, you need to know what's the maximum size of bag you're allowed to bring. The good news is that I've done the research for you.
Their is no bad news.
What I've noticed is that although every airline has its own rules, they are all fairly similar. The rule of thumb is you are allowed 45 linear inches or 114cm, including wheels and handle. Linear inches are determined by simply adding up each measurement. For example 20 cm + 40 cm + 54cm = 114 is just as good as 21cm + 42cm + 52cm = 114cm. However, do note that no measurement is allowed being longer than the indicated limits. So you cannot bring in a bag that's 10cm + 10cm + 94cm = 114cm.
In terms of weight, your carry-on and its contents is usually allowed weighing up to 10kg or 20lbs. Remember that when shopping for your cabin bag, their weights vary widely.
Furthermore, I read some places that European airlines tend to have tighter limits. I've determined that that is not true. However, by far the best idea is always to check with the airlines themselves. I simply cannot guarantee that they will accept "But Juan said it was ok" as a valid reason to let you board with hand baggage that does not conform to their rules.
Here's a small sample of airlines' and the IATA's (International Air Traffic Association) size weight limits:
I hope this helped you. Please feel free to ask me any questions. And, I wish you great travelling!