Boot life varies between 10-15 years or 100,000 - 250,000 miles depending on driving habits (life is reduced by city driving and cold winter weather). Boots should be inspected frequently after 100,000 miles for signs of splitting and gease leakage. If caught early, before alot of grease leaks out, you can simply buy two $30 boot kits from Toyota discount dealers like 1sttoyotaparts.com Each kit comes with two super high quality genuine Toyota boots, Toyota boot grease and Toyota boot clamps. Have a Toyota dealer or Toyota speciaty shop install the new boots and then you can drive another 10-15 years or 100,000 - 250,000 troublefree miles.
Most owners do not understand the factory original axles / CV joints will last 500,000 miles if never starved of grease due to torn boots, so they let auto shops and parts stores talk them into buying replacement rebuilt axles whenever the boots tear. Then they end up with auto parts store quality axles and boots which only last half as long.
Thank you.