I get a minimum of 7 years out of mine, sometimes 10 years.
Half of my stuff is older, no computers or memories to keep running; the other half have memories and/or computers.
Every car has a battery tender on it except the '96 Breeze, which gets run almost every day.
The battery in my '93 Pathfinder was almost 11 years old, just happened to notice the date tag and replaced it just to cover my butt.
I have a restoration battery that's a bit weak - it'll charge, then drop to 12.25V after a couple weeks sitting disconnected - but the PO let a cell get pretty dry.
Optimas I've had went 10 years easily.