At 69,000 miles I wouldnt be worrying about it. I would wait until 100,000 miles to change them.
When you do change them, you want to get a special sparkplug socket that had a sparkplug boot inside of it. That will hold the sparkplug inside the socket and will make the job much easier.
Its not all that hard of a job to do, but it does require some patience. Most important of all, make sure that you let the engine sit overnight before you remove the sparkplugs. The cylinder heads are made of of aluminum, so its easy to strip the threads. If you let the engine cool completely by letting it sit overnight, it will lessen the chance of stripping the threads.