Grand Marquis spark plug change?

Greetings all, this past June I purchased a MINT '09 Mercury that had about 46,xxx on the dash. Since then, it's been on several road trips and performed flawlessly, putting on about 5000 miles prior to my storing it in the garage for the winter. Here's my question/concern; I plan on having it fully serviced in the spring, so would it be necessary to chng out the plugs due to the age as opposed to the low mileage? No lights on, doesn't sputter, and it's a turn key and go. I just don't want the plugs to "freeze" trying to get them out when it's due according to the schedule, Thnx.