This doesn't have to be complicated. As has been mentioned you can see if pads are worn out. Depending on wheels you won't even need to remove the tires. Look at the pads from both the front and rear of the calipers.

I have never found that the pads didn't need changing when the brake warning light came on. They were not good enough for any significant number of miles before changing. I also replace the rotors and the sensors each time. If the pads on one side are bad I replace the other side at the same time.

I don't take any chances with losing stopping capability. I don't know why anyone would. If it were a budget issue I would cut the budget somewhere else. You never know when you might need all the stopping power it has to offer. Never wise to compromise safety.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas