Since I ruined a few primo shortfills when I added OOD nic that had turned 'peppery' I made a point of keeping a list of what I've bought and BBE dates on my computer that I update any time I buy more juice.
It's not exactly exciting, but it wasn't until I listed it that I realised I had enough juice to last 18 months and a lot of it was getting to vape or bin time. I vaped it because I'm a tightarse.
I've made an effort to only buy juice when I need to but never quite managed it yet but I've got it down to having a 6 month supply before I start restocking, but at the moment my stash looks quite restrained and lives in a tupperware box in my fridge.