Older skin requires special care and a lot of hydration. That is why it is suggested that sulfates, which are found in cleansers, may be too drying for aging skin, per She Finds.
Since older skin already has less oil production, the use of sulfates will continue to dry aging skin. So, if clients can avoid sulfates, it will help the skin feel more hydrated and less irritated from dryness.
However, using sulfates isn't the worst thing in the world, but if it is part of a client's routine make sure they include extra layers of hydration after.