I started reloading in 2001. I decided not to try annealing until it became necessary.
It took until 2006 for me to get my first split case-- a 30-06. At the time, I was always full-length resizing, and I traced back through my notes and found out I had loaded these cases 4 times, and these had come to me at least 1-fired.
My first trick was to go back and estimate the number of loadings of all my batches. I had good notes, and I just traced each batch through its various loadings. I think 4 or 5 was the top number. I then made a rule: all brass got marked in its notes with a Roman numeral. Roman numerals are handy because IV is one less than V, IX is one less than X, and so on. When I had to add a 'I' in front of a number, I'd anneal.
Since 2006, I've not had a split case. I can't tell you offhand how many loadings I've been through, or what's the top number of loadings for any of my batches, but I'm happy with the result. Just guessing, I'd say it's in the neighborhood of 20 loadings for some of the 30-06.
I will also say that annealing 270 WIN before sizing into 25-06 makes the job much easier. It also feels good burning all those gay cases before knocking the queer out of them.
Most recently, I've started neck sizing with Lee collet dies on some of my most-used chamberings. That should drive the numbers up even more.
