Absolutely. Your septic system is designed to handle the water from a "typical household." The average family uses between 150 and 300 gallons per day. Anything you can do to cut back on water consumption will extend the life of your leaching device. As a matter of fact, if you use no water (in reality we know this is ridiculous), your leaching device will never fail. The point here is: water consumption is directly connected to system life. If houses are constructed or retrofitted with low flush toilets and low-use shower heads, this is good for the system.
Another point: some systems fail due to overconsumption of water. Sometimes a toilet will leak can mean an additional 100 gallons of water per day going into the system. Or sump pumps, which are not supposed to empty into the system, can saturate the system with water and cause it to fail.