when to change spark plugs on 2007 Jeep Commander

When do the spark plugs need to be changed on my 07 Commander with 39,000 miles?

2 answers 2 comments
100,000 miles
Owners manual says to change them every 30,000 miles
Here is an online copy of your owners manual: http://www.jeep.com/en/owners/manuals/index.html
Look under the maintenance section.
Thanks for your help!