I'll also add that at least one airline has just recently dropped their allowable size from 62 inches (157.5 cm) to 55 inches (140 cm):
Checked baggage allowance | Virgin Australia
And at least one airline is in the process of changing their carry-on policies:
Carry-on Baggage | Jetstar
It is possible that other airlines may do similar things over the next year or so. Check, check, and check again before you fly.