I play with my girlfriend and we both always upgrade the trinkets accordingly at level 9, where as so far we haven't seen anyone else upgrade theirs.
It's basic stuff like this, which can save your life and help your team out. Even in my Platinum games I more often than not see people not upgrading and just using wards no matter what the opponent is, either they're lazy or they just refuse to deal with that.
P.S.: Certain matches require the basic warding trinket, which I fully understand and support.