Casual never means sloppy. Even if you changed the heels to flats, they should be attractive and coordinated to the outfit. They should be clean and in good condition. Too often you see a woman dressed very nicely, but her shoes are worn at the heels to the point that the leather of the back of the shoe has been damaged. Her look is totally ruined by such carelessness and neglect. A favorite pair of shoes should be taken care of. Check the soles and heels and have repairs made before the damage goes too far. If the damage has gone too far, it's time to replace them.
Time to check your footwear?