I agree about its being fine to use cheaper and easier to find products. However, I do think that it makes a difference to be consistent about using CG products, i.e., those without silicones and sulfate detergents. While rare use isn't going to set someone's hair back to Day 1 of their CG journey, it can still have a negative effect on the condition of the hair, and that can be cumulative if used repeatedly.
Peace,
Morgan

Baby Fine 3B, low porosity, normal density and elasticity
CGing since July 2008