There is no real way to give a recommendation unless you know exactly what you are trying to treat symptoms wise - but more particularly in Chinese Medicine diagnostic terms with supporting signs and symptoms. I'll say two general things, however.
First, within Chinese Medicine individual herbs are rarely if ever used by most practitioners. Instead formulas are used which are generally far more effective, more directed, and less likely to cause other issues including tolerance.
Second, on the issue of tolerance, there is a point where either you have resolved the issues and you simply don't need treatment any longer (people many times take things just out of habit, long after when they actually need them). More likely, however, the less precise your herbal treatment is (again in Chinese Medicine terms) the less completely you will resolve the issues at hand leading to eventual "tolerance".
In this case tolerance isn't really tolerance per se, but you have literally only worked on the surface of what your causal factors are so that's as far as things will progress/resolve (hence the importance of good diagnosis before beginning treatment).