85 or 8.5? i have a fairly fresh mint 19.2 vm installation that takes only 7.3 gb and a full 18.3 in a separate partition that is less than 10.
i tend to be a bit (i feel) over-cautious when it comes to backups. i have 27 snapshots of my five month old bodhi linux 5.1 installation that take up just about 43 gb of space in addition to the monthly clonezilla images i make.
i do keep all of mine on external drives just in case the internal one goes without warning though.