It all depends on what happens during the course of the year, on how much of the spending that was included in the budget was actually included in the main estimates when they were tabled. If there's a sizable amount that was not included, then you're going to have at least one estimate shortly after the tabling, sometime in the spring of the new fiscal year.
Then a lot depends upon what happens during the course of the year. Are there things that were unanticipated that have to be addressed, for which funds have to be reallocated from one department to another in order to manage a crisis or emergency of some sort? That would mean you would have to have at least another supplementary estimate on top of that, if not two.
I really don't have a problem with the three supplementary estimates, but I do have a problem when a lot of the spending that could have been included in the main estimates is not.