It depends on a few factors. The quality of the original rotor, driving habits, climate. I would not swap out an OEM Advics Toyota for an aftermarket unless it's EBC or something. No overt puslation or warping from the factory on a Toyota Matrix for 17 years, and it surivived a failed brake hose, excessive heat, etc without warping.
I probably was too slothful and never broke them free, so come time to replace them... the rust weld was brutally too great for the usual advised tools. So I bought junkyard knuckles from a California car on Ebay. Got new OEM rotors from a Dealer.
I'm not pushy, but the habitual "cheap rotor with every brake swap" some guys do here is a false economy imo because they're using poor quality cast iron to begin with. Get an Advics, and the rotor should not warp in a noticeable manner.