It really depends on how long your brass lasts with your loads, and how many pieces you get back after whatever you engage in that counts as your recreational shooting.
I shoot USPSA, and get out to about 4 matches a month and shoot between 400-500 depending if i get in some practice and round counts of the matches. I did this with various rigs with .45, 9, and .40. With 9mm and 45, I could get away with having about 2000 pieces of brass on hand. This is mainly because with 9mm, I could always go home with more brass than I produced because all the guys who didn't reload use it and leave it/give it away. With .45 I could always go home with more brass than I produced at one match because that match seemed to have a lot of people with money to throw away, and thus lots of once fired .45 brass. Heck, even when it wasn't that match, if I marked my brass in .45 I could almost always get about 80% of it back. .40 on the other hand is the most popular cartridge at our local matches, and almost everyone who reloads shoots it. So the brass vanishes. If i get below about 3000 pieces, I know i have to start looking for some once fired .40 online. With lots of diligence and scrounging, 6000 pieces turns into 3000 pieces in about 12-16 months.
.308 form my bolt action? I can account for every piece ever, and a couple hundred pieces keeps me supplied sufficiently compared to my free time and access to rifle ranges. My semi- autos in .308 and .223 are bit more problematic and I didn't bother reloading for them until ammo prices skyrocketed.