Good rinsing is probably more critical than state of inflation. FWIW my wife has a Zeagle, used extensively for NW diving for ~5 years. Then retired to tropical use for the next 10 years so it gets used well for 1-2 weeks every year or 2. Inside is always fresh water rinsed. At the end of use is it disinfected, rinsed well, emptied as much as possible over a couple days, then collapsed but not 'vacuumed flat'. It's faded on the outside, showing it's age, but never had a leak.
Our BP&W are treated in a similar fashion, both over 10 years old. I have a Dive Rite that has a bladder like the Zeagle.
One of the worst things you can do is let salt accumulate on the inside.
The inflator is generally more of a problem than the BC itself. I don't know if they changed it but the original Zeagle inflator (years ago) sucked, and the replacement was not much better.
To Air is Human,
To Respire, Divine.