Excess baggage takes on several definitions within the airline industry.

Having too many bags will cost you. So will bags that are overweight or over-sized.

Let's consider a checked bag that weighs 75 lbs. The weight charge alone on the baggage fee menu for major carriers typically runs about $100. That charge comes in addition to the baggage fee. At 100 lbs., many carriers won't accept it at any price.

If your suitcase exceeds size dimensions (usually the height, length and width in inches must be less than 62), there will be another charge -- often about $100 -- for exceeding the linear limits.

So a 70 lb. bag that exceeds 62 linear inches could cost about $235. It's like paying for another passenger.

On low-cost carriers, the fees can be even higher.

Ryanair charges a penalty of €20/£20 ($26-$31 USD) for every kilogram (2.2 lbs.) above their 15-20 kg. (33-44 lbs.) limits on weight. This policy is about more than adding revenue -- it's a clear way of saying "no" to people with heavy bags.

So the penalty on that 70 lb. bag on Ryanair would be about $365 USD.

Airlines have been charging extra for heavy luggage for many years. But the charges will continue rise and expand because it's now accepted practice and steady revenue. Some people never learn. They pay these fees!

Beyond this initial expense, there are many other ways excess baggage will devalue your trip...