There's an add-on that will run a check monthly.

Do I ever need to manually re-check the parity or does it do that on its own?

 

It will only do a parity check when you tell it to do a check. You can use the unRAID add-on to do it monthly automatically. I would recommend you do regular parity checks, monthly will work.

 

Otherwise, say you go 6 months with no checks and a drive gets corrupted and then another drive fails. The corrupted drive may prevent you from properly rebuilding the failed drive.

 

Peter