How often should you change your spark plugs?

I have a 2003 Chevy Trailblazer, with 52,000k. Is it time for me to change the plugs and wires? If so, is there a certain plug that is better than others? Or are they all the same?How often should you change your spark plugs?
Spark plugs in modern vehicles are platinum tipped and do not require maintenance as often. I have seen as many as 120,000 miles out of a set of plugs before they start causing problems, but they can start breaking down as early as 60,000 miles. Your particular vehicle lists a spark plug change interval at 100,000 miles. I would always suggest changing the plugs with what was original from the factory, as this is the plug that the engine was designed with. If you are not having any engine concerns, I would go by the schedule provided in your owner's manual.How often should you change your spark plugs?
If your trailblazer is still getting the same gas mileage and no drop off of engine performance, I would not change the plugs yet. The factory is claiming that you should not need to change the plugs and wires until the vehicle reaches100,000 miles. I have not had to change my 1999 GM vehicle's plugs and wires yet. I have not noticed any drop-off in performance or gas mileage. I do on a routine basis check the condition of the ignition coil wires to check for possible wear. If you feel that you do need to change your plugs and wires always use AC Delco parts for your GM vehicle. I have found good success using these parts.
Are you sure that this vehicle has wires? If it does then I would change them every 100,000 miles. I've usually traded in a car before I've every replaced the wires. As long as they don't get damaged, I'd leave them alone. The plugs should be changed every 30,000 miles and the best bet is what came on the vehicle originally. I don't trust the 100,000 mile tune up bit. Even new plugs wear out and emissions and fuel economy will suffer.
Check your owners manual. Latter engines go longer with out plug changes up to 100,000. Look for AC plugs for that car. (or denso since AC no longer makes their own plugs) Wires would only need to be changed if there is a problem. Spark jumping, or to much resistance in wire.
Yes, it's good time to change plugs, but use only those that are specified for this car - buy them from the dealer. It might be OK to change just plugs alone if you don't have any problems (e.g cracks, misfiring) with the wires right now.
these must be pretty good iridium mostly comes from meteors

http://www.densoproducts.com/resultsSear

any plug is ok, your best off just replacing them with what you have, don't go to a dealer they will triple the price of the same plug you can buy at any auto parts store (a typical plug is less then $4)
I use A/C plugs and heavy duty life time wires



yes it's time for you to change them
with today's long lasting wires and plugs you can get a lot of miles out of them,,but it is best to change plugs at or around 25-30.000,,and the wires at 50-60.000,,this way the stay in good shape,,they will last a lot longer,,but the heat from today's engines is much hotter than the older ones was,,they only used a 180 degree thermostat,,today's cars run a 195 degrees,,there's a lot of difference,,as for your vehicle,,its about time to change the plugs and the wires,,just to be safe,,on your vehicle,,be sure when you take it to have it serviced,,that the check all the fittings in the front so that they can be greased,,i had one this week in my shop that had not had the fittings put in it from the factory,,and had not been greased yet,,otherwise your OK,,just keep up[ all the regular maintenance on it,,and it will last a long time,,i do this for a living,,i hope this help,s.
change ur plugs every 30,000 wires maybe every 60,000 and as far as spark plugs i have had great luck with the autolite plugs u can get them any where or u can go with OEM AC Delco plugs which are alittle more exspensive you dont have to go over board with a exspensive spark plug
The Trailblazer uses coil on plug ignition, there are no wires. I have 2002 Trailblazer with about the same amount of miles and I don't believe the plugs have ever been changed, and aren't in bad condition to need replacement. Your best bet would be to inspect the plugs for buildup or excessive wear on the electrodes before buying new ones.