The process of change is constant. You must remember this critical point. You cannot relax your guard. Since change is always present, learn to live and enjoy the process. Human nature like routine and comfort. You must find ways in balancing change with the need for stability. A way of doing this is to alter your routine and patterns a bit at a time. If you go to the movies each weekend, one week try the middle of the week. If you go to the same restaurant, experiment with a new place twice a month. If you love reading mystery novels, try poetry or non-fiction as part of the overall mix.
Go to the library to have a quiet time to read. Visit a coffee shop of choice and just watch. Call that friend you were meaning to call and talk. If you introduce change in minor ways into your life you will keep you spiritual rhythms in tune with the symphony of life. This will not prevent those major catalyst of change. Those moments or events that propel you to new directions in your journey. However, it will condition you and guide you because you are not afraid of change. Sustainability is being open to a life of constant change while ensuring the harmony of your life.