The quick answer is no – if you’re still getting the results you want from your shampoo then keep using it!
However, what should be happening (particularly if you’re using professional shampoo and not doing anything too drastic* to your hair) is that your hair should be improving over time with use of a good shampoo. If this is happening you will definitely need to change shampoos to one that is going to be right for your hair type now, not necessarily what your hair type was 6 months ago.
Keep in mind if you are using a shampoo as a maintenance product and your hair isn’t being altered too much over time you will be able to use the same shampoo as long as you like.
I recommend selecting your shampoo by identifying the biggest problem you have with your hair. For example if you’re a blonde and you hate that yellow/gold tinge your hair gets then Blondes & All violet toning shampoo is the best one for you. OR if you have fine hair that you just want more body then Extravagance Volumising shampoo is the best selection. By doing this you will then also likely address other problems that might be second on your list such as dryness, lack of shine etc.
Sometimes it might be about having the right combination of products so if you’re unsure check with Sara at ME&MY or your ME&MY stockist for your personal Care Factor Plan∞!
*drastic – this can include chemical services (bleaching, colouring, perming), swimming in salt &/or chlorinated water, heat styling more than once a week, dietary changes, medications, hormonal changes etc