Now that just about all my shooting is at an indoor range, I usually only go twice a month. Each time, I'll take two 100-round boxes of reloads for whatever I'm shooting and typically finish all of it before leaving. I focus on my K9 and 1911s since these are what I have set aside for defense and feel proficiency is a is well worth the 300-400 a month (again, at an indoor range).
If I bring something other than the K9 or a 1911, it's usually something that isn't intended for defense, so it's all about fun and I don't put many through these (less than a box, usually).
So, I'll say 200 rounds each range visit.