Check the manual for recommended replacement intervals. Pulling your plugs has the potential of breaking them in your cylinder heads, causing a headache and creating more costs. I wouldn't pull them unless you have the time and money to deal with replacing them.
How exactly are you gauging your acceleration? It is much more likely that you have become accustomed to the power the car has verses it actually being down on power. With that being said, I believe (and don't quote me here) that the service interval for your car is 100,000 miles for replacing the spark plugs