I always figured foil was just for lazy cooks who didn't want to actually clean, and I was kind of proud of scrubbing my pans raw every time. Then my sister stayed with us for a month and lined every single pan before roasting anything, and I bit my tongue about it the whole time. When she left I finally tried it on a batch of chicken thighs that always leave that black crusty mess, and the foil lifted right off with everything stuck to it. The pan underneath looked brand new and I just stood there feeling dumb about all the hours I wasted with steel wool. Your mileage may vary with really high heat, but for normal oven stuff this honestly changed how I do dishes.