All these are examples of how procrastinating can cost you money. It's a smart and frugal behavior to anticipate your needs for replacing or acquiring a product. This way you can watch for a sale, visit online sites and set up alerts for sales, and watch for coupons at vendors you may use.
As for your stockpile inventory at home, never take the last of an item from your shelves without putting that item on your next shopping list. I actually have a threshold level of some things like paper towels (like 10 left) where I'll add it to my grocery tracker app and start looking for deals. Remember, some sales cycles are 12 weeks long, and if an item was just on sale it might not be again for a few months.
Now, I've got to check my stockpile...