I think you guys are a bit quick here. There are some questions to ask yourself:
1. What schools are you shooting for?
2. Are you in a profession that shows a good grasp of quantitative skills? Did you do an undergrad degree in something that shows a good grasp of those skills?
3. Do you think with review you could up your quant score?
The first question is obvious, but worth stating: if you're not looking to go to the very top schools, your score, including your quant is perfectly fine.
The second is less so. If you were an art history major who went on to work at a museum, I think it would be a mistake to simply dismiss this as "oh, well he got a 700+, he shouldn't retake." But if you use math regularly or you've done well in math type classes before, I wouldn't worry too much about it -- your time is better spent writing good essays.
The third is also pretty obvious. If you're unlikely to improve your quant more than a couple points even after study, don't bother.