Someone once asked me how many batches of beer I've made. That's a good question, and it requires some creative accounting. My numbers are fuzzy because I have not kept track of everything.
When I first started making beer I didn't keep track at all. It was: make beer, drink beer. At the time, I only did kits and established recipes found on Al Gore's young internet. This was around 1995-1997. I have no idea how many batches I made back then.
I took a bit of a hiatus (9 years or so) and started brewing again in 2006. Since then I have increasingly improved my record keeping. This is mostly a result of the fact that I have been experimenting more, and I sometimes forget when I brewed something and don't know if it is time to bottle or what it was I brewed. With 3-4 batches going at a time (as opposed to 1) I need to keep better track of what I got.
I first recorded my brewing activities on iCal (24 batches recorded). Eventually, I started using a notebook. So far I have recorded 23 batches in the notebook.
So, long story short. I estimate that I have brewed about 75 batches. I think that is conservative, but I am going to use that number as the official tally. I brewed a cream ale last night. I am going to consider that to be #75.
So, I've brewed 75 batches (at least). At 5 gallons a batch, that's 375 gallons and about 3750 bottles of beer.