When I started collecting a few C&R weapons, it led to gathering a bunch of .30 and .50 caliber ammo cans which necessitated the creation of a spreadsheet to track exactly what was stored where.
As long as I am diligent about updating it after acquisitions or range trips, a quick glance is all that is needed to keep abreast of my current inventory, and what needs replenishing. This has allowed me to buy for my needs on the dips in the recent market.
I also use the same spreadsheet to track my reloads and component supply. Again, updating it after each loading session is required to track inventory and needs accurately.
One .50 caliber can is still marked for miscellaneous ammo. It is mostly filled with ammo for which I currently own only one or no weapons, along with excess rounds for a few calibers that do not fit in their own specifically marked cans.
My ammo inventory reflects what I own. More toys in a particular caliber, means more ammo is kept on hand.
I do not ever think anyone can ever have too much ammo. What I don't shoot can be used for barter, and may soon be more accepted than currency.