It depends up the the state of the file system, the size of the files you normally mutate/create , and how full the RAID volume is. Under normal conditions, you should just leave it alone.
If you create and mutate lots of relatively very large files ( 10's of MB or more ) then you should periodically check. That's a "yellow alert" state. The HFS+ auto defragmentation system avoids 20MB and larger files. So those won't autocorrect over time if not deleted over time.
If your RAID volume gets tp about 65-75% full and also have the first condition, then that is definitely a "red alert". You need to check more often than above. With lots of free space, there is usually always room for HFS+ to find a large number of sequential blocks to store large files. HFS+ is not designed with volumes filled to the brim in mind (actually no File system likes to be in that state. But HFS+ automatic housekeeping even less so). Small files that may occasionally drifted into "mostly free zone" causing fragmentation but they will be incrementally cleared away. But the incrementally defragmenting system needs room to work in while still "open for business" services files.
Pragmatically, throwing out large, old "junk" files periodically is better than to run a program to keep reshuffling the deck chairs.