Yep!
When one of the four cars is do for an oil change, I have the correct oil for the temp range encountered during the run, and an oil filter sitting and ready to go.
All bought cheaply.
There is no sin in buying ahead.
It simply planning.
An oil change is never a surprise, nor is needing shampoo, laundry detergent or toilet paper.
Planning does save you money, when you take advantage of very favorable pricing on items you'll certainly use.