How long do Iridium plugs last?

I know the Nissan/NGK original plugs were good for 60,000miles but this seller on ebay says 250,000 for the iridium plugs.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1864335304

 

I'm sceptical to say the least.

Does anyone have the answer?.

 

and - Shameless Plug - anybody want a catchy domain name?

mine's for sale. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=2058136155

 

If you care to look in the far sale section I am selling whole sets of Denso Iridiums for £55 delivered the same as those in the Ebay thing, only mine are the right ones..

 

That mileage thing is bollox, i think they last about 30,000 miles, not 100% sure.

 

If the picture is what he is sellin they are IQ16's, which are not only too hot (By 2 grades) they are the wrong ones.

You need IK's not IQ's.