A certain team I've been trying to encourage to pair more often. They tend to work solo most of the time, and only pair when they feel there is a need for knowledge transfer. Yesterday morning we were talking about it, and one of the team members said, "We only need to pair when it's necessary, right?" I replied that I agreed with the words she was saying, but that I thought they had a tendency to underestimate when it was necessary.
A few minutes later, during the daily stand-up I had an opportunity to mention it again. The task board showed three items in process and one ready to start. Another team member said she had completed an item the day before and was available to start another. As she started to move the last item into the "in progress" column, I mentioned the value of keeping work-in-process to a minimum so that the team could pull items fluidly all the way across to "accepted."
"No problem," she said, "there are seven of us. We can handle four items simultaneously." So, there was my opportunity. I just took the attitude that pairing was assumed. I said, "Actually, there are three pairs plus one single. You've already got three items in flight. As I see it, you're already fully loaded. If anything, you should probably swarm one of the in-flight items until it's completed, rather than adding more. Otherwise, you're going to end up with incomplete work at the end of the iteration."