I opted in around eight weeks post-op. If the next question is about the difference it made, your guess is as good as mine. So many variable play a part in recovery/repair. My thinking is, if the money is available, history of cancer low, and even a chance it will help, why not.
Yo, Maz....if you read the novella of my experience via my shitloads of posts in here, you'll see that I pretty much noticed nothing until day 108 or so.
I went back and looked at the timeline of my recovery and my knee was quite noticeably curing at 92 days.
At about 108 days, I was feeling like I had a bionic knee. Got a buddy getting a multitude of injuries stem cell'd with Dr. Rebecca soon. I was skimming this thread, showing him how it went for me. His story will be interesting. He has had a shitload of injuries including eight skull fractures (all at the same time) that caused him to lose all hearing in one ear and half in his other ear. In the course of the multiple treatments he'll do, he's really hoping to recover at least some of the hearing in the ear that still works.