At the end of the day, it just comes down to reads. If you can't make a read, don't have a read, then don't fold KK. But to NEVER fold KK is not the best way to play them, imo.

I will say this though, I almost NEVER go AI with KK unless I'm a short stack. You want to weed the field, but you want action. AI pf with a deep stack is only going to get called by AA, or by the short stacked desperate guy. I often call someone's AI with KK and they usually NEVER have AA. Why? Because they pushed and didn't want me to call. They almost always have QQ, JJ, AQ, or AK. AA will usually smooth call unless they are an inexperienced player. AA is very easy to read on an inexperienced player. Less so online, but live it's very easy.