I bought 2L of 100mg/mL nic base in 100% VG from RTS Vapes (Nicotine Giant now) in 2015.  I left it in the original brown, PET bottles, wrapped in bubblewrap, in the shipping box.  I stashed them in the bottom of my bathroom linen closet (cooler part of the house and out of the way) to break down later.  Life went on, and I forgot they were there for 2 years!  When I decanted them, there was just a very slightly visible tinge of any color to it.  It had no taste nor smell either.  I figured if it stayed that clear even with 2 years of just closet storage...I'd keep buying my nic in 100% VG.  That was even before I'd read what Kurt had said.