The Speedo Endurance suits last a lot longer than the standard suits.
Drying your suit will have a huge effect. Putting in a bag wet/damp will promote mildew which will cause premature deterioration.
I will even lay my suit out in the trunk rather than leave it in the bad.
http://www.speedousa.com/helpdesk/index.jsp?display=product&subdisplay=productCare
How should I care for my Speedo swimsuit?
Pool chemicals and oil residues can be particularly damaging to swimwear containing Lycra® spandex. To prevent chemical damage to SPEEDO® swimwear, rinse your SPEEDO® suit in cold water immediately after each use. Do not wash suit with any detergent. Always hang-dry your suit in a well-ventilated space, as mildew will cause premature deterioration of swimwear containing Lycra® spandex.
Remember that loose fitting garments do not wear as well as those that conform to the body. When putting on your SPEEDO® suit, do not pull too hard on the fabric as it may damage. It is best to pull the suit up onto the body in stages, holding the SPEEDO® suit at the leg openings.