It might be a bit premature but I replace my own TM batteries every other year. It's cheap insurance that you'll never have a precious fishing day ruined, and I've seen a double-truckload of trolling motors with burnt windings and crusty brushes from running on low voltage.
You asked.....but knew beforehand that you were not willing to "start fresh", so go for it. The cost of fresh brushes, seals, and a new armature is 380.00 plus labor (2.7 hrs.)
I have kids to put through college, so please holler when she "just doesn't have the power she used to have, and sucks the batteries dead in 1/2 the time it used to". 😊