Yes, autumn is quite busy.
I changed a 24 oz paintball tank today. I got 4 months out of it. When I was emptying it, I found that there was a ton of CO2 left in it even though the gauge read zero. Prolly could have gone a few more weeks on it.
More verbose! I am sure most every one is pretty busy over time with their tanks.
That is a really long time I think. I have never tried or thought of trying CO2 but lately I have become more curious, so I could grow some plants I might otherwise not be able to.