Rob,
Here is a short story that may be useful to you. Even though at age 56, I had been having increasing hip pain for almost 15 years, my x-rays did not look horrible; narrowing yes, but not terrible. When I first met with Dr. Gross, he actually spent almost an hour with me trying to figure out if there was some other option that I might pursue rather than a replacement. He finally said that a CTscan would give us a lot more information. Two hours later when we looked at the CT scan, it was immediately obvious to both of us that my hip was shot, in a way that did not show up on the x-rays. When I spoke to him after surgery, he said that the timing was perfect, and it was amazing that I had remained active on that hip. There was a sizable cyst that was indicated on the CT scan, but did not really show up on the x-rays.
So, do not consider x-rays to necessarily be the final word. Your symptoms tell you a lot about your hip, and if you wait too long, a resurfacing may be difficult to do.
If you believe in resurfacing and are a good candidate, my own belief is that the affect on your quality of life should be the prime timing determinant, not the x-ray.
John