BLE-enabled Quarq power meters do NOT require periodic factory torque calibration. The power meter's slope (set during the factory calibration) is very stable and can be trusted over the life of the product.
XX1 Mountain Bike Power Meter: A calibration adjustment may be required when changing from one chainring size to another on this power meter. If you are not changing chainrings, the calibration does NOT require adjustment. (This does NOT include the current XX1 Eagle power meter.)
Any Power Meter that uses a CR2450 battery: Any power meter that uses this battery size requires re-calibration when changing to a different tooth count or chainring brand. If you are not changing chainrings, the calibration does NOT require adjustment.
Please contact Quarq Customer Service with your power meter serial number if you need more information.