Great question. I am an experience designer. I always try to figure out the best method tocut through the noise of all the other "UXers". I need potential clients to know I can walk the walk and not just talk the talk.
I consider myself qualified - here's how I show you that I am qualified:
First and foremost, if someone tells you they can solve your problems by becoming your full-time UX employee it is a sign that they are not qualified.
Before you hire a UXer to come into your organization, assess the UX maturity level of you and your team. There are usually latent cultural issues within organizations that make it difficult for them to work with UX people because the UXer is there to teach everyone in the organization how to do their job differently. That's a big pill to swallow. Regardless of ego, if your team isn't aware of this then it's something you can do now to prepare them for when you do hire a UX expert.
UX Debt: assess the total debt that has accumulated in your organization. This is the list of items that need to be changed or updated or require new processes around in order to "fix" your problems. You could hire a UXer to just get this far with everything so you can decide how you'd like to move forward with next steps.
Phase-Driven: the type of UX help you need today, will be different from what you need tomorrow. Depending on your organization, you don't need to hire a UX person full-time on a salary. Too many companies out there are trying to hire their "UX guy" or "UX girl" that's going to solve all their problems. This is incorrect. The UX professional should be hired to teach your organization how to become design thinkers and who learn how to solve your organization's problems on their own. Based on your UX maturity level, you will at first need someone to come in and work hands on with you at the leadership level, and also with your team. After the initial phase (about 3 months), the UXer should start pulling back as you watch your organization begin to function a bit differently than it was before. Now, instead of people running from the blame of customer's problems, they are all focused around the customer waiting for the customer to let them know what they need next.
Of course, if you need visual design (branding, identity, interface elements, etc) then once you bring in your UX expert it will be part of your plan. It's much cheaper to sub out the styleguide you need for your product when you have specific design specs and creative direction.