The brake warning light is on in my 2010 LR4 HSE (about 59k on the odometer), but I am wondering if I will need to replace the sensor in addition to the pads? I don't want to go through all of the effort to replace the pads only for the light to stay on. Does anyone have knowledge on the sensor lifespan?

 

Anytime you replace pads, replace sensor. Sensors grounds the system and turns on the light. Most times when I remove a sensor it snaps. Not that expensive.

 

Yes - you have to replace the sensor. It's just a wire loop at the end of a wire. As the pads wear down the loop touches the rotor and gets worn through, triggering the light. So it's a single use product.
You can buy aftermarket ones that work fine on amazon eBay etc for $10-15
You need one for the front (left hand wheel) and one for the rear (right hand wheel). Front and rear are a different part number
Do you know if you need to change front or rear pads (or both)
Btw it typically triggers around 4mm of pad life left so there is usually plenty of time