I carry 13-14 in the field. I like to have enough on hand at home to check zero periodically and troubleshoot through the season if I take a tumble on the rifle/scope; 20-25+ additional is what I prefer to have on hand for that task.
Generally I don't load less then 100 rounds in a setting. I'll roll up 100 rounds for each hunting rifle every year before season. Rarely do I have any left after a season, but if I do they get relegated to the practice box. I like my entire batch to be the same lots occasionally I'll have to split a load due to running out of powder in a canister mid load in which case samples are fired across the crono and grouped to verify any significant differences. So in short I guess 100 rounds per hunting rifle every year. Target rounds are a much higher depending on rifle.
I shoot and reload ammo all year long. I go to the range at least one day every week that I'm home, all year. At each range session I start off by shooting two or more cylinders or clips through each of 3 or 4 pistols, offhand, at my 8" steel gong at 25 yards. I then move over to the main rifle range and shoot at least 10 rounds from field positions at the 100 to 430 yard steel gongs front each of 2 to 4 rifles (.223 to .300 Wby). After that I go over to the Skeet range and shoot 3-4 rounds of Skeet.
Before going on any hunt I verify with at least 2 shots on paper at targets at 100, 200, 300, and 430 yards with the rifle that I will use on that hunt.
When hunting anything here in Montana, in the field I carry 3 cartridges in the magazine and 10 in my belt ammo pouch. For foreign hunts ands hunts outside of Montana I take two 20 round boxes of ammo for each rifle that I bring, and again in the field I'll have 3 in the magazine and 10 in the belt pouch.