Thanks Stedman, I do understand the weather issue but both bats were used in above 60 degree weather. I try to control her use as much as possible, I won't let her hit off a machine with her game bat, store it indoors only, and not to use it below 60(I know it has more to do with the ball hardness not the bat temp). I tried my best to keep the bat in the best condition, yet her Louisville and past Demarini held up to machines and cold weather like a rock.
No issues with the endloaded bat she's a tad bigger and stronger than most girls. She's hitting roughly 200-500 balls a week with her lessons, practices and at home work.
I'm not a bat expert but interested to hear what others say about the life expectancy of a bat. I can only assume manufacturers worked diligently with a design staff and agreed upon a number of hits that their bat should be able to endure. I think you get where I'm going with this. Perhaps the bat has simply run out its life expectancy. Food for thought.
Just like most everything else in today's world a lot of thought is put into product reliability. Can they make a bat that would almost assuredly last a life time? Sure, but you may not like the performance. Plus, companies need to sell bats. Producing bats that last a life time doesn't benefit them in the long run. You buy a high-end bat with expectations. In order to achieve that performance it means taking a design that takes it to a razor's edge in technology and only supporting it via warranty/guarantee for what they deem favors the company. In the big picture, if they have 1 or 2 out of 1000 sold be returned for replacement they can look at their earnings and say "We Win."
Notice bat manufacturers warranty is over a time span, not the number of times it strikes a ball. That warranty starts with the purchase date on your receipt. They have done the math and come up with a formula on what they deem "normal use." That way the bat should last thru that time span. Notice nobody offers extended warranties on bats? There's a reason for it.
Don't get me wrong, keep sending it back for replacement. You basically paid for that insurance. Frustrating for sure. Frustrating to you not them. It's simply the cost of doing business.
Some bats are going to exceed expectations of reliability. 200-500 hits a week in practice and games sounds like a lot of use. Not all those hits are going to be in the sweet spot which adds extra stress to a bat. Even with the best of care, which from your post sounds like you are doing more than most, that's a lot of use. Buying more than 1 bat or expecting to replace it more often than the average use player, might be your only option if you are satisfied with that brand and model.
Again, I'd like to see what others have to say on this subject.