I changed my plugs fairly recently, maybe 7-10k miles ago... is it necessary to get a new set to put in after the test?

 

You don't have to but I'd say you should. 10,000 miles isn't recent in my book lol

 

Well I'm going to have to get new ones when/if I boost this summer.

I'll double check the last time I changed em, if its more recent than I thought, do I just tell the guy to keep the old ones in?

 

You only have 4 plugs, and at $2.50-4 per plug (if your not running basic ngk's) i wouldnt question it and just change em. I changed mine probably way more often than I needed to. I changed mine probably every 2-3 oil changes maybe less or more, that was at $2.79 per plug NGK