Oly everything oxidizes... The 2 main culprits are oxygen and heat.
We generally 'freeze' nicotine because it oxidizes fastest. The colder it is, the slower the molecules move leads to less oxidation.... And the less air in the bottle,the less oxidation.
If you had room you could put your VG and PG in the fridge or freezer, and it would be slightly? better, but it's not necessary.
A cool room and not direct sunlight. That being said, when it's 100+ ALL damn summer, my VG/PV is in the closet of our den... and it's just fine