Its endurance is 6-9 hr longer than the average ultra portable laptop. Apple consultant, former employee, and fan. In general, a Macbook air is going to have a useful life of about 3 to 5 years. After about 3 years, you may notice things seem slower on your computer than it does on newer computers. You will probably have to select low settings and you can be sure that your Macbook air will overheat.