Slightly lengthly satellite radio question...?

Ok I had Sirius service while back, but cancelled it year or so later. I since moved and when I unpacked my old receiver and hooked it up, I was still getting service so I shut my mouth and took advantage. Problem is, my receiver is old now and is failing me so I was wondering, if I get a new receiver do I have to set it up with Sirius again and jeopardize my free service or will it just switch service from the old unit to the new? Btw, I don't mind paying for it if I have to, but I just wanted to continue to take advantage of someone else's mistake lol.