give 10% and everyone gets one
also give 10%, and we often need more than one of them
give 20% and we often need one of them to solve our mana problems
And there are still other handy items that we build sometimes, like 
and they all give even more CDR
What are we supposed to do with all this CDR? We cap it with just our core builds. And when you don't get lane income, wasting money on excess stats is a bad idea.
Maybe Riot could change the 5% CDR mastery so that it caps CDR at 50% but does not give any immediately? It'd be way more appreciated by supports lategame I think.
The only items AP Supports buy from that list is either one of the starter items, frostqueen/mountain/coin/ and then either locket or zekes. Every other item should NEVER be bought on a support. if you're buying those, you're doing something WRONG. Not Riot's fault for cdr overload, it's your fault for poor itemization.
