Because it's hard to know when you're going to get a flat, it's always good to have extra tubes on hand. Specialized's Thorn Resistant Tube is thicker on the road side for puncture protection and thinner on the rim side for weight savings.
I've been commuting to work for about 15 years now and do approximately 6 miles each way in San Francisco. After a series of flats I decided to splurge and grab a set of these for my Specialized, and was thinking - Great The extra thickness will definitely decrease my chances of a flat, enough to offset the extra weight. Unfortunately, both tubes lasted less than 4 months due to the valve stem ripping while inflating. I usually fill my tires about every 3 days and am very easy while attaching the pump head and taking it off. I've had basic cheapo tubes last a year or more and was very disappointed for the amount of money they cost. Maybe I just got part of a bad batch....
Bottom LineNo, I would not recommend this to a friend