I'm running low now. I have 8 litres Castrol Vecton 10w40 E6/E9 and 5 litres Liquimoly Top Tec 4100 5w40.
I gave up trying to hoard oil because there's always something different I want to try.
I'll be buying 20 litres Mobil Delvac MX ESP 15w40 (I think this is the same as Mobil Delvac Extreme in the US?) in the next few months. It'll probably last me 6 months.
I'm down ~15 quarts from my last update. Used ~5 each of Kirkland, M1 EP and PUP. Unless some crazy deal pops up I won't be getting any more until next year. I am keeping an eye on Costco to see if the price will drop.
24 qts of Castrol semisynthetic 5W-20
15 qts Pennzoil Platinum 5W-30
6 qts Shell Rotella Gas and Truck 5W-30
5 qts Pennzoil Platinum High Mileage 5W-30
I aim to have about 2 yrs worth of oil on hand. That way I can wait to add when the price&sale is right. Current stash of about 50 qts is just about right.
Enough for 12-18 months of changes. But I maintain 6 vehicles for friends and family members. I stocked up on Havoline 6 qt. boxes before they went up in price.