Every reverse osmosis system requires periodic maintenance to keep your water as pure as possible. If you don't replace your filters and membrane every so often, you risk lowering the quality of your water and damaging or clogging the system. Refer to the owner's manual for how often to replace your filters, but this will also depend on the quality of the water in your area. Although it doesn't require professional plumbing skills to change the filters yourself, you'll want to read the manufacturer's step-by-step instructions carefully on how to replace them. Make sure to purchase the right filters that need replacing since there are both carbon pre-filters and carbon post-filters for reverse osmosis systems.