Your gums may recede (shrink back) as you get older, and your teeth may become a little more sensitive as a result. Your dentist or hygienist will be able to show you the best way to brush to keep any gum problems under control. They may also suggest a mouthwash to deal with the sensitivity.
You may find it harder to clean your teeth if you have problems moving your hands or arms, or if your eyesight is less than perfect. Again, you can get help and advice on the best aids to use. A magnifying mirror and a good light are often helpful.