There are a handful of varying conditions that play a part in when you will need to wax your vehicle. If you keep your vehicle parked in a garage or another area where it would be safe from the elements, you can probably get away with waxing your vehicle just twice a year. If your vehicle is mainly parked outside and is exposed to the elements more often, it might be a better idea to wax your vehicle every 3-4 months.
We know what you're thinking, "I can just get my vehicle waxed at the car wash for a couple extra bucks the next time I get my vehicle washed." While this is true, most car washing places will wax your vehicle as it is rolling through the line, these waxes are generally very thin, and sometimes do not even last for a week! Roll up your sleeves, and put in a little elbow grease in order to give your vehicles paint job the protection it needs. Remember, it is recommended to wait around a year since your vehicle has been painted before applying wax.
When you wax your car, truck, or SUV, you're giving it added protection from rust, salt, and other corrosive materials. Since we live in an area that gets a lot of snow each year, our vehicles are going to be faces with large amounts of salt, and other materials sprayed on the roads to keep the ice off. By waxing your vehicle before the snow starts to fall, you're well on your way to keeping the exterior of your vehicle protected.
One thing to note: while the waxing at car wash stations generally won't get the job done, it is important to keep the undercarriage of your vehicle clean during the winter months. Salt and other corrosive materials will build up underneath your vehicle, and washing them away is generally the best option. Just be sure to try and choose a warmer day when you wash your vehicle, or find a friend with a car lift in a heated shop. You don't want your doors freezing shut on you after going through the car wash.