With proper care, your sunglasses can be worn for many years. We have hand made our products so that they withstand variable and extreme conditions.
The best thing you can do for the wood is to make sure they are properly conditioned. We recommend Lemon oil, which can be found at health food stores and markets, or online. Using a soft cloth, pour 1 teaspoon of your chosen oil on to the cloth and then use the cloth over the surface of the wood, buffing slightly. This will aid in keeping your glasses clean and conditioned and will increase and improve their life.
The biggest challenge is temperature. This means if you leave your sunglasses in a car on a hot sunny day, the high temperature has the ability to swell the wood. Same with leaving it in the car on a particularly cold day or night. Humidity control is also important. Swelling and shrinking increase the possibility of cracking at the time and in the future. Full submergence in water is not recommended for the integrity of the wood itself.
When you are not wearing your sunglasses, be sure that they are protected in their case to protect them from an overly wet or dry environment.