I carry a plug kit with me and have used more than once it in the past, they work good most of the time...
I have plugged many a tire in my automotive career but times they are a changing when it comes to tires and tire safty...
Since model year 2008 we have tire pressure monitoring on all cars and trucks under 10,,000 lbs GVW and tire dealers are getting more strick about date codes, load and speed ratings and tire pressures due to lawsuits...
Until recently just plugging a tubeless tire was the standard tire repair unless it was on the sidewall or was too big of a hole to plug... In some states (at least in NY starting in 2001) depending on the load and speed rating and tread depth of the tires the repair must be what they call plug patched... This requires dismounting the tire and using a special drill bit you clean out the hole and then clean the inside of the tire near the hole...Glue is applied to this plug patch thing that looks like a regular radial tire patch made onto a long rubber plug with a small steel pin on the end...The plug is pulled through the newly drilled and enlarged hole (drilling the hole gets rid of any sharp edges that could hurt the plug) from the inside out and you have a very safe (if done correctly) permanent tire repair (it cannot pull out like regular plug or fall off like a regular patch can) that should be safe at speed and be able to handle the weight as good as the rest of the tire...
More information here...
http://www.tirerack.com/tires/tiretech/ ... ?techid=77
Some car companies say to to NEVER use a repaired tire and that tires should always be replaced in pairs...
All wheel drive vehicles (not 4wheel drive although you never want to run different sizes on them either) should also have all four tires replaced at the same time because of drive line wear by using tires that are different diameter...
I am not sure if in my area (SFBay) you could find someone that does plug patches as it is hard enough to find a tire shop that even does Road Force Balancing but if you want to repair your tire more permanently instead of replacing them you might want to try it...