A good rule of thumb - if the battery has been in long enough to give it's complete service life, you can all-but guarantee that the terminals/ cables are corroded. It's common to scuff & clean the terminal, but on sealed cables this does not address the corrosion that will be present in the stranded copper at the terminal junction.
If it's time to change a battery - it's typically time to change terminals and clean the cable. New terminals (replace both) can be picked up for a few bucks while at the parts store picking up the battery, and since the cables are already disconnected and the battery is out of the box - it's perfect time to change them.
Something else to check while you're doing the work - I found a vacuum leak in the plastic lines that feed the front axle actuator where they passed by the battery. It seems the battery venting reacted with a section of the tubing causing it to degrade, become brittle, and had begun leaking. I cut out the hard/ brittle section of both lines and replaced with a rubber vacuum hose jumper. Front axle actuator works without hesitation now.
/K