I've driven many cars over the years. Not once has a vent ever broken.
Which cars are you driving where they break often?
Which cars are you driving where they break often?
My experience is that as the car gets older it is common for the vents to lose the capability to stay pointed where I place them. As in: you point them where you want and they flip back all the way to one side as soon as you let go.
(Hot climate here, with several months of "a/c set to max during the whole trip" per year)
More modern cars of decent build do not have this issue.