I agree.  At 7 years, I'd just do it as preventative maintenance.
Usually batteries give some indication of failure, where you can still
start the car, but realize it's not turning over right.   But then,
I've also seen them go with no warning at all.  Particularly if it gets
very cold out.   And give the small cost of a battery compared with the
cost of a service call or tow plus a new battery, it's obvious what to
do.