Depending on your location, ensuring that the right type of tire is fitted at the right time of year could improve both the life of the tire and your safety on the road. It’s generally accepted that a winter tire (designated M+S) offers far superior performance and grip to a summer or all-season tire when the temperature is below 7 degrees (44 F). Constructed of a softer rubber compound than a summer tire, a winter tire will equally wear much quicker than a summer tire in warmer temperatures.
Our advice for optimal safety / life of a tire is to ensure you have the most appropriate tires fitted to suit the weather conditions. Of course, you would not want to be changing tires on a regular basis. You can usually do this bi-annually (start / end of winter season), but this could extend the life of your winter tires dramatically. (Generally speaking, winter tires are more expensive than their summer counter-parts.)
Rental cars are generally maintained to a very high standard; however, you should still check the tread depth and general condition of all tires when renting a car before you accept. Returning a damaged tire (possibly due to excess wear) is likely to be your responsibility should you need to replace it.