I think the default setting is usually to enable it?
I have a dim understand of it from memory. As I recall, enabling it provides slightly faster performance but has a slight risk of data corruption in cases of a bad shutdown--like from a power outage. It can also have consequences when using RAID.
The geekiest thing to do is to enable it, but use a UPS (uninterruptible power supply) to eliminate the risk from power failure.
Me? I've always left it enabled and haven't knowingly suffered any negative consequences.