I got my initial test 3 weeks before starting T, and I got another 3 months later to see where I was. In that time, I had gone from the female range for T into the higher end of average on the male range. Hormones fluctuate all the time.
You really wouldn't want to wait that long between tests. Aside from the changes and side effects, there's no way to tell internally how your body is responding to T. In addition to the testosterone test, my doctor runs tests to look at my red blood cell count and my kidney/liver function. You'll want to have that information ASAP if something isn't right.
I'm sure it'll vary by doctor. Mine tells people in advance that if they don't show up to quarterly appointments and blood work for the first year, that she won't approve refills. After the first year, she wants people in twice a year. After the second year, annually. So perhaps once you've been on T for a little while, you can get away with a yearly visit. But I would guess not right away.
My doctor has me come in at the mid-point in my shot cycle for blood work. I come back and see her about a week later and we go over results.
Hope this helps!
