Really. I have no idea which brand or product will perform the way a client needs it to at their home. I have no idea if they will like the scent of a product and if it will compliment everything else in their daily ritual. Performance and satisfaction are both completely subjective. There are no definitive means for an individual, professional or not, to say unequivocally that any one product will work for someone else. This is a fact. Unfortunately, most hairdressers attempt to up-sell products like a snake oil charlatan, particularly if they are working in a conventional hair salon. They have no idea or don't care, that this practice is at the top of the list of things clients dislike.
What a responsible hairdresser should offer is information and education on the types of products that could work or might work for someone. As frustrating as that may be, there is no way to know with 100% certainty that any product will work as advertised until a client gets it home and uses it as part of their normal routine. When it comes to hair cosmetics, it is typically a trial and error scenario, particularly for those with curly*, wavy or fine hair. I know this product truth is likely frustrating to hear. If it makes things easier, most people struggle with hair products because their hair hasn't been cut well and is severely underperforming. In this way, a really good cut takes much of the pressure off of a product's need to perform. This is the real root of the problem, pun intended.
Are expensive salon products even worth it then? This isn't for me or any other hairdresser to say. It is a case by case situation. What I tell my clients is this. If they like a certain product, if it works and makes them happy, I do not care where it was purchased or how much it cost. More than ever, I have clients who are making their own products at home or using things purchased from health food shops. I encourage and support all of this enthusiastically.
In the end, I use my experience in this industry to honesty educate my clients so that they are well informed. A well-informed client is much better positioned to begin the necessary trial and error practice of finding a product that can offer them the results they seek. Make no mistake, a great haircut is where it all starts. It provides the visual and emotional motivation most clients have been needing to help them on their journey.
*Specifically for those with curly hair, there is a lot of information out there regarding things like micro-fibre towels, sulphates and silicone. My stance is, to each their own. I am firmly against adherence to any particular ritual as a 'one size fits all' ideology. While many of the strict methods and practices work for some people, there are plenty of others who choose whatever gives them the best result with the least amount of effort. As stated earlier, a good hairdresser will simply educate clients on various options and let them discover and decide what is best for them. It bears repeating, a great haircut will provide a shape that can support effort and effortlessness equally.