I agree with Afraser​ this is about giving your body the best chance to be rid of it all. I did a combination of Tamoxifen, Letrozole and back to Tamoxifen for a total of 10 years. My time flies, although early days I thought I was on it for 5 years only but things evolve, plans change, but now it is behind me.
I had bone density testing at the start and all good.
Like some of us I had twinges, aches and pains as my body adjusted to the medication regime. Emotionally at times it was hard yards as fatigue is also a factor early days. Once through those hurdles I am out the other side with some aches and pains but I am still here and NED!
Best wishes with your decision, there's no right or wrong it is what you and your Oncologist decide suits best and is tweaked as you go along, as you can see from my brief explanation above.
Take care