Should I change my plugs?

I know that the suggested interval is 100K but my car is almost 9 years old with just a little over 50K on the odometer and I was questioning whether a spark plug change would be in order due to its age? The car starts without a hiccup each and every time it's turned over and there is never anything unusual coming out of the exhaust pipe.

While we're on the subject, are there any age specific, not mileage, repairs or maintenance that should check out or be concerned with? I already change my air and cabin filters long before due and I'm changing the oil in this thing about every 5k-6k (even though I know it's not necessary. The radiator was just flushed and the power steering fluid was changed out. Nothing seems to be leaking and the seals around all the suspension parts appear intact.

I know the answer is probably going to be, if it works, don't fix it. But sorry, I just had to ask.