A mirror array is not a backup. So therefor I would use at least one of those extra drives for a weekly backup of your data. You want some sort of not real-time backup in case you get cryptoed for example
For me it started in AOL, once banned for taking over the Disney chat I then learned about IRC and from there I learned of usenet. Been usenet ever since.
Back in the AOL days you would hang out in the Warez chat room, and you would subscribe to download files using email as the delivery. Chat for a few minutes and then next time you log in. You’ve got files!