I buy the best pads possible, no warrantee needed, and rotors just not a cheap brand, and those not every time.
Rotors don't have to be replaced each time, but, some vehicles have barely adequate rotors which warp easily. So that's a case by case vehicle model issue, and cheap brands make people falsely assume all rotors warp easily on that vehicle etc.
I'm a mail carrier, I assure you I find the limits of brake parts, and I am naturally very hard on brakes. My current brakes on my 98 Limited, are OEM pads front and rear, and rotors that were about $35 each, all from Rock Auto, and the rotors new about two brake jobs ago. I replace rotors when I perceive that there is enough metal worn to be close to needing turned or replaced.
Today's vehicles come with thin rotors, older Fords used to be 1.25" thick parts, and could be turned multiple times. Now your luck if you can get one turned once or twice. Others mentioned it too, it costs too much to have a rotor turned, and a new one is not much more, and easier to get. Turning rotors used to be $5, and new ones were $25 or not much more. Now there are way too many brands to choose from, although they don't cost much more.
Concentrate on pad quality and brake fluid, those are most important. Regards,