My answer will be brief but has several aspects:

• Backup records locally (potentially on your computer and as printouts)
• Backup records on a separate hard drive (thumb drive, etc.)
• Backup records in the cloud (the account service, dropbox, box, drive, etc.)

Also, I would recommend keeping records based on the legal needs of your company. Some companies have a legal responsibility to maintain records much longer than companies in other industries.

It's always good to have backup copies. Hard drives may fail, businesses may close shop, so always be prepared.