From the moment of the first purchase (payment for services or any other operation). This is the most convenient scheme for calculatingvalidshop ru, since the interest-free days start from the date of the first purchase.
After each operation. Such a scheme is quite difficult to meet, since large banks do not practice it. In this case, each payment will have its own grace period,track2shop and you need to pay off the debt in the same order in which the purchases were made.