Please pay attention to the part about grooves, important info for your concerns
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Shops replacing pads at 2-3mm is just good business practice, no fault in that as most customers will not be having their vehicles looked at for quite some time.
I only takes a few minutes and that is all that is needed, 99.99% of the time as long as the brakes have been properly maintained or the rotors have had a very rough life or a very long life.
If you just take a look at them once in awhile and replace when down to 1mm or so you will be fine, use them up!
Buy some pads, keep them in the car if on a trip or swap before you go, keep them else where until you need them.
Unless your rotors are cracked, not heat checked which is fine if not severe, or slightly grooved they do not need changed, new pads wear into the grooves and work perfectly fine, I have ran grooved rotors without issue for years of service.
If you feel vibration and think the rotors are warped, that hardly ever happens.
What does happen is getting the brakes nice and hot and coming to a stop and sitting there with your foot on the brake pedal transferring pad material to the rotors and now you have a spot that makes it feel like warped.
Often that will clean off with some hard use of the brakes, if not then some brake cleaner and steel wool, if that does not work then they might need turned.
I have driven at least 1 million miles, huge amount of it hauling arse, raced cars, trucks, some rallies, etc...and had one set of rotors turned, ever, broke a couple and just replaced pads and then rotors as needed the rest of the time and get a huge amount of life out of rotors and I use brakes hard.
