How long on hormone blocker medication

Goodness - I must be so lucky to have had so few side effects form Letrozole - this only makes a little more concerned about swapping over to Tamoxifan. Fingers crossed that my next bone density has stabilised so that I have a stronger argument for continuing on Letrozole although my oncologist is certainly expecting there to be further deterioration. My spine was OK bur hip was in the lower ‘yellow zone’. This time also having my wrist measured as oncologist says often arthritis in spine can mask deterioration in bone density. It appears that we all have very different side effects and thus opinions - also medicos seem to vary in their opinions and treatment. All makes a little confusing for we patients.