I see a lot of racquets brought into Dick's Sporting Goods with grips in horrible shape. Some of them are so melted that the grip is actually glued to the handle! Today's cushioned, rubbery grips don't hold up very well in the heat and humidity like the old leather grips used to.
Summertime in South Carolina can raise the temperature to well over 120 degrees in the trunk of your car and this is a bad place to leave your bag for 4-10 hours a day before you have to play a match. Even your garage can become too hot and humid for your sticks.
The heat (or extreme cold) is bad for your string and your frame as well. While different strings have their own elasticity characteristics, extreme temperature fluctuations will accelerate any normal tension loss causing strings to play 'dead' after only a couple weeks. Likewise, your frame is under tremendous stress just from the tension of your strings and heating it up in your vehicle can prove very costly.
LEAVE YOUR BAG INSIDE!
You should always take your racquet bag inside the house after playing and remove any racquets that you used so the grips can sufficiently dry. This is not necessary if you have one of those backpack style bags.
If you must take your bag to work because you have to go straight to a match afterward, take your bag inside if at all possible.
Today, many manufacturers offer bags with a thermal shield to protect your frames from extreme temperatures. Toss one of those frozen chill packs into the racquet pocket if you have to leave your bag in the car for an extended period of time.
