double folded question!
first of all age has everything to do with it. Start as early as 14-16 you are almost guaranteed quick and rather fully immersive transition experience. At that stage even a month makes a difference.
However, the older one gets, lets say beyond 25, changes slow down, further into older age and changes take eons to manifest.
Pass the 30's and it seems one is climbing Himalayas to get to the pinnacle of visual femininity.
For most, the ungifted in the fem look department, surgery becomes a holy grail, and there still if someone had been bestowed the bloky thick representation of natures real man scenario, then even surgery outcome borders on iffy.