Odds of Hanging On
If you build a respectable practice and prove yourself trustworthy with your client's needs for privacy, are discrete, and are a talented healer, then odds are your patients will keep you on retainer for many, many years to come.
However, celebrity is a fickle beast and one negative review from a disgruntled client could turn your list sour on you.
Burn-out is also a real issue, considering how demanding your high paying clientele will be. No matter how well you're doing, make sure you have a nice nest egg to fall back on, in case you decide to pack it in for a quieter, simple life amongst the little people.