Depends on the doctor. Brassard's nurses said two months minimum, or until it feels comfortable. I didn't feel like testing it for quite a while longer than that. 🙂
Honestly, one month was too soon even for the incisions to have healed or even all the stitches to be out, and I would not have wanted to risk it - there are some VERY bad complications possible from overstraining a brand-new vagina, including fistula and prolapse, and that's aside from the serious risk of infection. One month was still soon enough that they had all these lectures and rules about being careful with the *dilator,* much less letting someone else hammer away in there.