Still a rookie owner here so apologize if this one is covered elsewhere. At 104,000Km do I just change my brake PADs or the PADs and Discs??? Car stops straight and without any shakes. Pedal travel is just about an inch further than a while ago.
If the MDX brakes without any steering wheel shakes and you are going for OEM pads; I would just do the pads. I would only replace the rotors if they are too thin. If it has been close or over 3 years, I would also look to replace brake fluid also.
Pad wear does not impact how far your pedal travels. The hydraulic caliper adjusts to always keep the pads in the same position. If the pedal actually feels different, you may have a fluid or brake booster problem. To know if you need pads/rotors, you'll need to inspect them.
There's no indicator, you'll need a clamping dial or other tool. If there's no vibration you could try to just replace the pads (if they even need replaced) and see how they hold up. I'm at 65k miles and pads still have a ton of life. Brake fluid is supposed to be flushed every 3 years btw.
I also pull each slider pin (one at a time), wipe it, re lube it with caliper grease (packets are at the check out counter at most parts stores, for .99), and slide it back in.
Then I do the 2nd one.
The pins are different and doing them separately ensures that that go back where they came from.
Some may say that the pins are interchangeable, but I got them backwards in my Integra and one stopped sliding, melted itself in to the caliper. I had to take the caliper with welded slider to a exhaust shop to have them heat it enough to remove it. Then I bought a new pin.
See items #8 & #14 on any Acura Online parts page, MDX, then, Chassis, then front brakes.