There are many things to take care of e.g. tire pressure, wheel alignment, the wear bar, etc.
There are two specification sets for tires including the tire manufacturer's specifications and the vehicle manufacturer's specifications. Whenever you take your car to a tire shop to get the tires changed, they have to meet these specifications by law. You can get a tire that goes above these specifications, but never below.
Probably the most important number for the common person to recognize is the recommended tire pressure on the vehicle manufacturer’s specifications on the driver’s door jamb sticker. (The tire manufacturer’s specifications on the tire itself include the maximum pressure that the tire can have, yet the maximum pressure isn’t necessarily the best pressure for the vehicle).
Tire pressure is measured in PSI (pounds per square inch) or KPA (Kilopascals) which are simply units of measurement for pressure. (Pressure is a force distributed over the surface area)
Tires can wear rapidly if they are not aligned properly, or the vehicle can pull to one side while driving.
The wear bar is a horizontal bar molded into the tire between the treads. The wear bar indicates safe tread depth. It is usually about 1/16 of an inch measured from the valley of the tread, but not as high as the tread itself when the tire is new. As the tread wears down, the wear bar becomes more visible. When the tread is even with the wear bar the tires should be changed.