The life of an Apple iPhone 17 Pro Max case isn't the same for everyone. It depends on the material, how well it was made, and how well you maintain it. If you take good care of your clear TPU case, it should remain in good condition for 3 to 12 months. If you take good care of your opaque TPU/silicone case, it should look great for 12 to 24 months.
Among Apple iPhone 17 Pro Max cases, SUPCASE phone cases feature a TPU and hard PC construction; with proper care, they typically retain their appearance for 18 to 36 months or even longer.