How often should a RAID consistency check be done?

I have a LaCie 60TB RAID array. I've had it for a couple of years, but I am wondering how often I should do a "Consistency Check" on it. I don't know a whole lot about RAIDs. It's formatted HFS+, so I think this is a different than defragmenting. LaCie don't mention doing this as a routine in the section of the manual regarding the subject.