Well, bully for you!
You must not work in a place where management cancels that already-approved leave, using the excuse of "operational need" (which is absolute BS, by they way) or calls you back because someone else quit or whatever.
We had a manager do her level best to try to cancel the leaves of people who had put in six months early, had it approved and so bought plane tickets and everything. It took formal grievances to make the manager stop canceling already approved time off.
