Don’t throw out fresh lemon slices that were used in drinks or any left-over fresh lemon. Keep them in a separate glass by the sink and use them to wipe the sink and prevent any build-up of lime scale. They are antibacterial too!
Also use fresh lemon to descale kettles: Place the juice of one lemon in your kettle. Fill with water until all the lime scale is immersed. Boil and leave overnight if possible. If your kettle is heavily scaled, repeat the process many times and use a dish-washing brush to help remove the lime scale (careful not to burn yourself though!).