I was interviewed for this article. https://www.houzz.com/magazine/how-much-does-it-cost-to-hire-an-interior-designer-stsetivw-vs~112598632
When hiring an interior designer it’s important to know what you are paying for and how. Ask the questions. Are products being suggested because that’s where a designer has the best mark-up or because it’s the best thing for your project? How is their time tracked?
The bottom line is hire the person that you feel will listen to you and help you realize your vision.