Thanks, realized it when I tried to do.
Another question, if we don't need the feature of the service pack, is it necessary to do service pack?
I found in all cases doing the service pack or not does not make any difference to our applications.
So should we do each service pack, or follow the rule that if we need the new feature then apply it, otherwise stay at the version when we installed them.
John pretty much answered your question.
My only suggestion would be, do not jump from your seat and apply service packs if they just came out. Even though they are extensively tested by Microsoft, issues may arise. Most recent one is/was with SQL 2012 SP2 and possible data corruption when doing online ReIndex on Ent. edition. A hotfix was provided few days after that.
By the way, I recently applied SQL2012 SP2 on one of my boxes and had no problems at all. I applied and tested the application on a test server though, but the process went smoothly on production and test box.
Just dropping my 2 cents.