For some strange reason always gone for the -R DVD blank discs.
I know a lot of forum members will disagree that the life time of the discs I buy won't be half as good as the more expensive branded names but have some as old and recorded in 2002 and still are readable. TDK fod DVD and MAXELL for CR-R.
Kept well away from sunlight or even artificial light should last years.
Backup on to USB Drives though.