Typical cycle life of a good quality designed Li-Ion battery pack like a 40V or 24V Strikemaster product is around 500 FULL charge and DISCHARGE cycles. I would not be surprised to see packs run 10 years depending on usage.
How the battery pack is designed for protection, safety and cell manufacturer used is very important to achieve good cycle life.
There is no memory effect like nickel based chemistries so you don’t have to worry about full discharging your Li-ion pack.
During fishing season, try your best to keep your pack warm prior to use especially if temps are below 4 degrees F.
At the end of season fully charge your Li-ion battery pack, store it somewhere around 50-80F and you will be good to go for next season.
Also once you start to notice your Li-ion battery starting to lose significant run time you will not have much time left before it needs to be replaced.