Basically at age 6 I went from a 4-oz bulb, that I think was injecting about 3 ounces each time which would have made 9 oz per round, to a bag that held 1 Imperial Qt ended up using that only 3 times
At age 9 I went from that to a 2 US qt bag.
At 11 I was allowed to have the final say on which bag to use. The first enema I took my 11th year was that same bag, but the second and third enema that year, I used a 2-imperial Quart bag that I believe my grandmother had bought for use on my mother. I still use that one occasionally.
When I was 12 and was fully self administering, I convinced Dad to let me use his 3-qt bag.
I used mostly the 2-imperial qt bag until I turned 16. It was at 16 that i bought my 4-qt "Great White" open-top bag
Still the only open-topper I use for enemas.
After I really used that "Great White" I found that the 2-qt bag just didn't feel the same any more and I bought myself a 3-qt bag, identical to Dad's from the same place. That has become my primary enema bag today, although I still keep that 2-imperial qt and a couple of 2-US qt bags around for occasions like foreplay enemas and similar.