Nowadays thats less than 10 drives. I literally just ordered 10 20 tb drives to fill my second nas.

I have two synolygy 1019+ with ds 517 expansion units. That 10 drives for each set. Technically i could set that up to have about 400 tb usable.

I buy factory recertified drives for about 200 ea. with a couple spares.yea its a chunk of change but not too crazy.

I have multiple friends with more than a pb.