TIPS: string tensions greater than the racquet's recommendations could damage the frame during stringing or while at play. Select a racquet that is designed to withstand high tension loads if it is desired in your game. For recreational play, 18-24lbs are average for badminton and low 50's to mid 60's for tennis, assuming a nylon based string is used.
TIPS: Polyester tennis strings are very stiff strings, made primarily for superior control, spin, and durability. However, it is low in power and can be uncomfortable on the arm. Lower the string tension by as much as 10% and/or use a hybrid set-up such as poly for the mains and nylon synthetic guts for the crosses could bring out the best for a poly on your racquet.
TIPS: a racquet should be kept at room temperature to maintain the string's characteristics and tension. Avoid storing a racquet in places like cars where temperature can be abrupt.