I don't have to worry about this because at my company we have a separate Disaster Recovery location with twin servers for all our production servers. I transfer and restore the weekly Full backups to the DR SQL servers. Every other day of the week, I transfer and restore Differential backups. Therefore, if there's ever a problem with restoring any of the backups, I'll know right away! So far, I haven't seen any issues. Typically, SQL Server backs up DBs reliably.