Having to regularly change my shampoo to prevent my hair from getting accustomed to it: is this a true statement?
No, this is not true: using a complete range of hair-care products on a regular and long-term basis will only improve the benefits brought to your hair.
sing your regular shampoo and conditioner on your hair will not lessen nor change their effect. What can change though is the quality of your hair, due to factors other than your hair-care products: weather, additional styling products, etc.
If your conditions change (ex: you have started colouring your hair), you can always switch hair-care range to adjust to these changes.
Despite changing hair-care range, remember your hair will never get accustomed to its properties, hence reducing its effects.
Garnier caters for all hair types and conditions, and offers complete ranges of hair-care products, including shampoos, conditioners and hair treatments (hair mask, hair serum, leave-in oil, etc.).