You may use both of these products as they have different purposes. The artnaturals Argan Thermal Shield can be used every day to protect your hair from heat damage. Apply before blow-drying, straightening, or curling your hair. The artnaturals Argan Oil Leave-In Conditioner adds additional moisture and rejuvenates your hair strands for easy detangling and styling. This product can be used once a week or once in two weeks. We suggest you not use the Leave-In Conditioner on a daily basis, since it may weigh down your hair, especially if your hair is thinner.