In the past, when shooting for close quarters practice or just plinking I use cheap ammo. For sight-in and distance shooting practice I use what I plan to shoot for those situations. Fortunately, I roll my own now so my cost stays down rather significantly. I've always had it drilled in to my head to practice how you play so I re-zeroed a few times a year with my SD and hunting ammo. That way I knew my firearm was tuned to the ammo I was using for real world shooting and adjusted for the seasons because it can affect the ballistics. I'm not as anal anymore, but I still check the zero a few times a year with the good stuff to stay on point.