Re using cast iron rings?

I've slapped them together with the same rings and even the same head gasket when I cracked a 351c head and it ran like a scalded dog until I sold it 4 years layer with no smoke. A piston ring will polish the bore after a while creating a very good seal. If you put a new ring in, you will HAVE to apply another cross hatch pattern to hold the oil to break in those new rings or else there will not be enough bite to run those rings in properly. If the rings are to be reused, just make sure the ring lands are clean and the rings float freely in them. I did a small mazda motor that had very smooth bores and the crank would turn as freely as a bike tire when the head was off. I pulled the pistons and hatched the cylinders again ( I installed 1 new piston/ring pack years ago with no cylinder prep and I dont think it ever seated so I was getting a pulsing blowby) but after all were criss hatched again, there was a noticeable difference in the drag of those rings. My blowby is much less pronounced now with hatched cylinders and will probably get better with a few hundred miles on them. In a perfect world with a perfect car budget, everything would get replaced right? Sometimes things are imperfect and sometimes that is not an issue.