I ususally carry two tubes and a patch kit.. If tube has done its time- I usually do not worry about repairing it.. Especially on way to work. I am in a hurry, no time to waste... Seems once in awhile repaired tubes do not take and have to change them soon after a repair.. Certainly don't have time on a work commute to repair tubes twice..
The second tube, I often carry in my jersey pocket..