Answer:
I recommend they purchase two new drives.
Step-by-step explanation:
When they purchase the new disk drives, the project documents should be backed up using one of the new drives(A) anytime it gets to half way full so that the project documents disk drive will not be pressured.
With the second new disk drive, it should be a backup to daily work data when work is done everyday(B), at the beginning of the day it will be refreshed of the new days data whiles the previous days data is moved to the project document files disk.
This will help when there is a crash. Because if disk B crashes the same data will be in the project document disk. And if the project document disk drive crashes the information can be found in disk A and disk B.