If you have the tires off and they are 10 years old, I would replace them (unless you are willing to turn off the TPMS system using the IIDTool or similar if they act up). They eventually develop tiny cracks from age and you can end up with slow air leaks even if the sensor itself it still running fine. If the sensors finally die in them before the tires wear out, you have to go through the trouble of dismounting and remounting the tire to replace one, assuming you know which one it is. Then you wonder if another one will go before you are ready to change tires again, which is frustrating.
You can get high quality Siemens/Continental VDO replacements off Rock Auto for a good price compared to dealers.