I mentioned this in my ET post, but DH and I had said the whole time we would do whatever the RE recommended. Initially, we were told that if we made it to a 5dt with an excellent blast, the recommendation would be to transfer one. However, yesterday with my legs in the stirrups and spread eagle, the RE says "We are transferring two blasts today. Okay?" We were speechless. RE left to wash his hands. After sensing the shock, when he came back he asked my age and told us that we could elect to transfer only one. However, his recommendation was to transfer both blasts. RE looked at me to make the call. I looked over at my husband and he blurted out "TWO!!" So, two we did.
This was a fresh cycle and now we have two on ice. My clinic freezes in pairs, so any future FET would have two transferred (assuming both survive the thaw).
I think it is a very personal decision. Yesterday, we both just knew that two was the right decision. GL!