I wouldn't recommend doing all this work getting them out just to reinstall them. It's not that bad when you consider they were in there for 4 years or 100,000 miles.
You may be able to find a better price on the plugs than what I quoted.
I don't recommend using anti-sleaze on spark plug threads (although admittedly I don't recommend the use of anti-sleaze at all).
I agree that the purpose of the 4 year interval is to keep the plug from getting stuck to the head.