Saline is perfectly safe to use to wash your eyes out if you get a foreign body in your eyes or your eyes become matted or experience a lot of discharge.
For day to day relief from persistent ocular irritation, burning, scratching, itching, etc., I would recommend you get into the routine of using artificial tears 2-4 times a day every day, even when your eyes feel good. This can provide more of a preventative benefit to limit how often and how severe your symptoms become.