In a full ring game what conditions would it be better to limp with KK UTG? I believe by raising UTG, you limit the competition and their starting hand range. Hoping for someone to open the door preflop can be dangerous and I'd rather have AA or AK but some people limp with KK.
My thoughts are:
considering a loose passive table. you raise more in an effort to scare. I like overbets here. 5BB... or more sometimes.

considering a loose aggressive table. you raise less hoping for a reraise. 2.5-3BB

cosidering a tight passive table. you raise less hoping for a reraise or one caller/shipper in the blinds.

considering a tight aggressive table. you raise more hoping for a reraise or one caller or shipper in the blinds.

its good to be the 1st raiser because if the pot is raise 3 times more. I'd consider folding in this case.