Ensure that you weigh your bags before you take your trip. The requirements vary by airline and destination as well as elite status in the airline's frequent flyer program. A quick check on the airline's web site will ensure that you have the correct information. Not having the correct weight and dimensions for your bag may result in excess baggage fees.
Also if you are connecting from one airline to the next the restrictions may be different by airline so check with all the airlines before you leave your home.