Most salons like myself 50% my income is generated from sales so I would say so yes.
It's not over night it took me many years to build up to how busy I am and even on my off days I seem to be dropping off environ orders all over down at various clients who don't have time to come in.
For ex I check my client cards see who might be due for facial or who needs more items usually you can tell average time then msg them see how they getting on and more then likely they reply " yes nearly finished bout my skin feeling dry can you suggest anything else " and that boosts a sale. So if clients feel they getting personal attention they usually are more loyal. Just in my personal experience . But depends from area to area I suppose.