My goal is to have enough lead, powder and primers for 20,000 rounds. I'm pretty sure I'm not too far off. 200 rounds a week for a year will go through 10,000+ rounds in a year. I figure if something crazy happens I'll be set along with having enough supplies to continue practicing for a little while along with being prepared for whatever. I'd need more storage space to increase these numbers.
Along with a nice pile of .22lr and a couple hundred factory rounds of each of the popular calibers I shoot and a couple hundred reloads for for each caliber I feel adequate.