As long as the iPad's battery life meets your usage, I wouldn't worry about battery health. It's a consumable so of course it's gonna wear down. The question is just whether it still lasts long enough between charges given your usage.Still using my Air 2 everyday. I bought it October 2014. I am getting a bit worried though. 5 years is a long run and I am not sure how to test the current battery condition.
We have a Mac Mini and I heard about something called Coconut. If anyone has a link to a testing process I would appreciate it.
I can't say for sure battery life is shorter but I do notice apps crashing like they are running out of ram. Scrolling through the FB app on the Marketplace especially it will eventually just crash.
I am considering a 10.5 Pro. I have an X but on my iPad I still enjoy having a Home button.
That said, if apps are frequently crashing on you, reckon it's probably time to replace the device.