I keep inventory. I have a list on my fridge for my deep freezer and pantry. I have a different one for my deep freeze and fridge freezer, because I've organized my fridge freezer into my 'once a month cooking' meals that I've made up. I don't do too much of the OAMC, but usually make double or triple batches of things that freeze well and I can just take out of the freezer and bake or defrost and re-heat.
I write down numbers on my sheet on the fridge (if there's canned tomatoes on the list for example, I'd write how many I'd used that week)...then, I update my computer list every Sunday/Monday- before my shopping day Tuesday.
On the computer list, I have what the last price I paid for the items listed- that way if I notice a good sale and have coupons and see that I'm running low, I'll stock a few more of those items when I go shopping.