This depends on what kind of work you are doing. If you are talking about web development, perhaps take a course online to refresh yourself and get a taste of the basics. You might check out this article to get you started. However, this question like asking "How important is it to learn how to turn left as a driver?" Sure it's important, but so are a lot of other things like shifting gears, looking in the mirrors, rules of the road, etc. So OO programming is only just a small part of a larger body of knowledge you should be acquiring if you want to be a great developer.
Andrew Wooldridge
eBay WebDev
This depends on what kind of work you are doing. If you are talking about web development, perhaps take a course online to refresh yourself and get a taste of the basics. You might check out this article to get you started. However, this question like asking "How important is it to learn how to turn left as a driver?" Sure it's important, but so are a lot of other things like shifting gears, looking in the mirrors, rules of the road, etc. So OO programming is only just a small part of a larger body of knowledge you should be acquiring if you want to be a great developer.