I rarely feel that way any more. I feel like I'm running out whenever I get to the point where I'm literally about to run out of ammunition, whether on the range or in the field.
As for my personal stock of ammunition, I essentially maintain a full ammo can for each of the calibers I own. If I dip into that can, then I'll work to fill it back up. Since only a certain amount of each caliber will fit into an ammo can, the amount for each caliber varies. For my .22 WMR, that's 3,500 rounds. For my .45 acp, that's about 1,200 rounds. Don't remember all the other amounts.