I don't know of any stat's after 5 years or 10 years on hormone suppression treatment. For me my decision was one of considering how important that part of the treatment was in terms of all the treatment I received. We all have different needs in terms of assurance and feeling we have done what we can.
I do have a friend who had hormone positive bc at 40 and was recommended chemo, radium and hormone treatment. She didn't finish chemo or radium. Probably did about 2/3 of both and refused the hormone treatment. At 50 she got bc again but in the other breast and it was a different bc altogether.
There are stories supporting very different approach to treatment but what is important is what you think for your treatment and your satisfaction that you have chosen the right treatment approach for you.