Are there any symptoms that indicate when to change the plugs in a 2005 Corvette?

i just change mine every 50K to avoid any fusing of the plugs. they need to be turned out to avoid electrolysis or corrosion. if that occurred, they will be very difficult to get off.

oh.. use anti-seize compound on the new plugs to make easy removal in the future.

Thanks to both of you for your help! I am the original owner and know they have not been changed out yet. I bought the new plugs at 100K but it has run so well that I've been waiting for some sign of a miss to replace them. Are there any tips I should know about as I tackle this project? The last ones I changed were in my C3.

I had no noticeable signs with my 2004 SUV with 122,000 miles. I just took it in to have them replaced & found that two of them were cracked. I get much better gas mileage now.

Or you could follow the recommended maintenance schedule in your owners manual.