I don't drive much and take short trips. I checked the battery voltage and it is 12.45 which is a bit undercharged. It always starts ok. Should I trickle charge the battery occasionally to bring up the voltage or just leave it alone? I have the original battery and with the engine running the voltage is 14V.
Sounds like everything is working normally including the driver. Better than trickle charging the battery is to get it out on the highway once a week and run it for a good 15 mile stretch. Short trips are extremely hard on an engine. All of the wear takes place in the first few minutes when the engine is cold. Very little wear takes place once it is warmed up. You are keeping the engine in the high-wear zone with only short-trip driving.
Air is drawn through the engine to suck out gas fumes to be burned, and the humidity in that air condenses and goes into the engine oil. That promotes corrosion and the formation of sludge. When the engine gets hot, that moisture vaporizes and gets drawn out. Water impedes the oil's ability to isolate moving parts. Most notably engine bearings will wear out quickly and pistons will scuff on the cylinder walls. Both of those are expensive repairs that shouldn't happen for at least 200,000 miles. If this is happening you will usually see evidence of that by water droplets clinging to the underside of the oil cap or the oil on it will have a milky white or light brown color.