Is the support period always five years?
No.
Five years is the minimum in normal cases, not the automatic answer for every product. The CRA says the support period must be at least five years unless the product is expected to be in use for less than five years. If the product is reasonably expected to remain in use for longer than five years, the support period should be longer.
Article 13(8), recital 60
section 4.5.2
points 114-115