Thirty years is the general life expectancy of a shingle, however the “30 year” name does not guarantee that they will last thirty years. 30 years is the life expectancy in ideal climates and conditions. Climates with high temperature shifts or a lot of sun have a lower life expectancy than climates with steady temperatures and a bit more shade. Generally the life of a 30 year shingle is around 15-20 years, for no climate is exactly what is needed to get the full 30 years. 30 year shingles often have warranties attached to them and depending on the company the warranties vary from 5 years to 20 years. 30 year impact resistant shingles vary in strength from class 1 to class 4. The type of class determines the material and the resistance of the shingle. Generally class 4 is the highest level of protection making the shingle less susceptible to hail damage or damage from other storms or weather debris. 30 year impact resistant shingles are beneficial in climates that receive a lot of storms such as hail. However the price difference between standard 30 year roofing and impact resistant 30 year roofing is substantial. On roof shingles, there are small rocks that can be knocked out of place in the case of a storm. If the stones are knocked out of place, the shingle becomes more susceptible to damage regardless if they are impact resistant or not. So the question being 30 year impact resistant roofing vs 30 year standard roofing roofing, which is worth it? The answer depends on the climate you live in, depending on the amount of hail or wind you get spending the extra money on a shingle that may get shredded or ripped off within a couple of years may not be worth it. In some climates where the weather is fairly mild with occasional storms impact resistant roofing may be a viable option for your home.