Most cars have power steering. The power steering system helps pump power steering fluid to hydraulic piston. The piston helps make turning the wheels easier. To ensure that everything is working correctly, you can check the power steering fluid level around every month and the color every 6 months.
While checking the power steering reservoir, notice if the fluid level is low. Fill to the correct level is needed. If you suspect a leak check the hoses in the power steering system and replace if needed.
If you notice the fluid color is fairly dark, its probably gone past the replacement date. It should be replaced according the owners manual suggestion.