Hi, sorry for the slow response... you snuck this one in on me.
I'd take it on a case-by-case basis. I use mostly OCC silver/gold alloy and UPOCC copper litz wire, this kind of wire does not seem to make the same improvements as conventional copper wire so I don't do cryo. There is a place nearby that has great facilities and prices, there are a couple of my cables cryo would probably help, like my SMC speaker cables that are made with 24g UPOCC copper wire. On connectors, the ones I use have been cryo'ed by the manufacturer.
I have not tried outlets as the Furutechs are already cryo'd so I can't share impressions of cryo vs non-cryo since they come cryo'd. I bet regular hospital grade outlets would benefit though.
