Edge AGM car / truck batteries are 100 % replacement for 4 years .
Edge AGM RV / Marine batteries are 100 % replacement for 2 years .
I have 7 years on my AGM car/truck batteries .
10 years is a common life for AGM batteries .
The advantages of Edge AGM are faster recharging times ,
Slower drawdown ,
no off-gassing ( can be inside ),
and no leakage issues .
As to lengthy stays , I have been doing the HD jumper cable
method for a dozen + years .
9 days no worries , as my pickup gets driven every 2 or 3 days .
I do not run my truck engine to charge the RV batts .
I just let them equalize .