Open your driver door. There should be a sticker on the panel that says what size tires are stock and how much air they need in them. Some can vary, as it depends on if and/or what you haul with your vehicle, weather, roads you drive on, etc. It's best to contact an experienced tire salesperson.
In studdable tires, there are little holes which are meant for the studs to go into. When tires have been driven on, little rocks get inside of the holes.
According to the U.S. Rubber Manufacturers Association, putting two snow/winter tires only on the front axle of any vehicle may cause the vehicle to experience adverse handling characteristics. This may result in an accident, which could cause serious injury or death. Read more here.
No matter what, tires wear out. Rotating your tires helps them last longer by changing the wear spots on the tires so that they will wear more evenly.
Every 5,000 miles for rear wheel drive vehicles. Every 3,000 for any other vehicles. A good rule of thumb is to rotate your tires every time you get an oil change.
When your steering wheel shakes while driving, it's usually a sign of the front being out of balance. Vibration of the seats is a sign of the rear being out of balance. It's a good idea to check the balance of your tires when these things happen before thinking other things are wrong with your vehicle.
The "P" here means "Passenger" vehicle, which means this tire is designed for passenger vehicles like cars, vans, 1/4 ton or 1/2 ton trucks, and SUVs.
Instead of the "P," there can be "LT," which means "Light Truck." These tires are meant for trucks that tow trailers or carry heavy loads, up to a 1-ton truck.
There also can be a "T" there. That means "Temporary" tire, like the doughnut tire in the trunk of a car. These tires are only meant to go up to 50 miles at up to 50 miles per hour.
Next, the 205:
The next 3 numbers after the letter(s) let us know the width of the tire in millimeters.
Next, the two digits after the width tell us the aspect ratio of the side wall. The 60 says the sidewall distance from the wheel rim to the outside of the tread is 60% of the section width. The lower the percentage, the lower-profile the tire is.
The next letter:
The "R" in this example means "radial." Radial means that the tire has radial construction where the body plies of the tire radiate outward from the center. Over 98% of all tires today are radial.
Instead, there could be a "D" or a "B." "D" means bias ply, which means the internal body plies crisscross on a diagonal pattern. "B," belted tires, are very similar to bias ply, but there's an extra layer of reinforcing belts under the tread area. Belted tires are not very common anymore.
The numbers at the very end are the tire and wheel diameter. In this example, this 16-inch diameter tire should be used on a 16-inch diameter wheel.