You know you have a problem if any of the following become apparent:
•    Open wounds or sores under the saddle area
•    White hairs
•    Hard lumps 
•    Rubs in the hair
•    Temporary swelling under the saddle after exercise
•    Muscle wastage in the saddle area, particularly behind the shoulder.

Sometimes a problem with your saddle fit is not so obvious and a behavioral problem or a performance issue is the first sign.  Often the saddle can be to blame when a sudden or progressive change in your horses behavior or performance occurs.
•    Objects to the saddle or girth
•    Fidgeting when mounting
•    Reluctance to go forwards
•    Hollowing and evading the contact
•    Bucking or rearing
•    Transition’s become hesitant/unbalanced.

•    Tree flex’s excessively
•    Saddle sits too low on the horses back, maybe even touching the withers
•    Saddle is sitting too high and tipping back, maybe pinching
•    The flocking is lumpy and uneven
•    Saddle is moving or bouncing.