Different surgeons tell you to do it differently. Discomfort the first few weeks and days is much closer than actual pain, but you will feel the stretching, and a big problem at first is pinching of the tissue inside. A neo vagina has more skin nerves inside than a born-with vagina, and is not as slippery normally. Getting the lube we use into the internal skin folds is the source of a lot of ouches. Like natal females though, we can also get infections that can intensify the discomfort by gobs.
I am at 16 weeks and use a 1 3/8" mint colored plastic dilator twice a day. This was the largest size I was prescribed, but I do use it more in a masturbation fashion which is where and what I am supposed to be doing. Orgasm can be a goal and I go for it.
My depth has varied a tiny bit over the last 4 months, but I am at the maximum depth my surgeon thinks I should have, so I am happy. At the end of July, I will go to one dilation per day, for the rest of my life, with time off for bad behavior!! Since I hit six weeks, I could count one sex session for one dilation session per day. Furthermore deponent saith not!!