These patch kits are a must! When I blow a tube, I usually put a new tube in and then patch when I get home. I have tubes with multiple patches & they are just as reliable as a brand new tube.
Glue, patches, sandpaper in the most compact kit I've found. I run through one of these a year commuting 22mi/day all year round in PDX. Good quality glue and patches. Thanks to the small box I can fit the patch kit, spare tube, two irons, 10 bucks, my cell phone, C02, and a pair of nitrile gloves in my 30 cube inch seat bag no sweat (ok - a little sweat).
I rarely use this patch kit because I don't get a lot of flats but it always works when I help someone stranded on the roadside who doesn't have a spare tube. On the few tubes of my own that I have patched, if I get a leak it isn't at the patch. Not much more that you could ask for.