Medication: Most medicine should be left at room temperature, but a car will rarely stay at that point when not in use.
Electronics: Beyond the expense of the devices themselves, gadgets like laptops, cell phones, and thumb drives contain information that could be easy to steal.
Sunscreen: Leaving it in the car on a hot day could reduce its effectiveness. Plus, the heat could cause it to explode, leaving you with a hot mess.
Water bottles: Letting a bottle sit in the sun and heat up could cause these chemicals to leach into the water. Plus, if the bottle has been lying around for a while, it could start harboring microorganisms.
Handbag: Leaving a purse or wallet in plain sight makes your car a target for thieves, even if you’ve locked your doors or taken the valuables out of your bag.
Glasses: Heat can warp plastic frames and make metal ones too hot to wear.
Important documents: Letting files like school transcripts or tax forms sit in your car while you run other errands or until you have time to take care of them leaves information vulnerable if anyone breaks into your vehicle
Wine: If the bottle gets too hot, the flavor could be affected, and the liquid could expand enough to seep around the cork or push the cork out a bit, contaminating the wine inside.
Young children: Even if you don’t expect an errand to take more than a few minutes, leaving children alone in the car on a hot day puts their safety at risk.