Plug replacement (was Autolite)

["Seattle Dan" <DanWeb@xxxxxxxxxxxx>]

How often do people change their plugs? I like to do my valves/TBs every 3k
or miles (I commute a lot) but I'm not overly crazy about changing my plugs
that often. I have thus far and, as Tom said, have found that fresh plugs do
make a big difference.  

I've love to know what the rest of you are doing as intervals (best to also
specify air/oil/hex head too as point of reference). 


If intervals are greater than the 3k miles, then is it possible to buy just
plug gaskets? I don't want to reuse a plug with it's already compressed
gasket.

Anyone have a source for the BMW NGKs that is less that around $34 for the 4
of them?

------------------------------