I got certified in 2000. I did my cert dives but that was it. To make this story as short as possible, I'm getting married in Sept. and our honeymoon is in the Bahamas. We get two free dives a day and I wanted to take advantage. My fiancee just finished her cert dives on the 9th in preperation.
Since I hadn't dove for six years, I signed up for a refresher course. It was $45 and about an hour of one-on-one time with an instructor. It was worth every penny. Things came back to me pretty quick, but I would not have felt comfortable getting in open water without this course. I've since got a few more dives in on my own, but the course is well worth it.
Now, obviously, you've not been out of the water as long as I had. However, like others have said, if you are asking the question you probably should take one.