Does the spacer need to be replaced every time its apart?
I doubt it would need replacing, don't think it would wear
I toss the spacers on steer, tag, drives and trailers axles. Reset preload using the two nut and two lock washer system. Once bearings and races are worn in you can't achieve preload by reusing the spacer. Wheel seals won't last long. I set all at zero end play. Stemco and Conmet love selling the re-bearing kits. But that's the way I do it, and don't have issues.