Dry camping and power supply

With all this charging and using (discharing) of the batteries, what is the average life and replacement cost of such a battery. I realize that is a difficult question to answer, but say you use your system 16 weeks out of a year. Run down to 50% and recharge each time daily. Have your unit in storage the remainder of the year. Can I expect the battery(ies) to last more than one season?
Sorry if this is a silly question, but I know nothing about batteries, generators, not solar panels.
thanks