Ring Alarm -- Retrofit or No?

I've been a longitme Slomin's customer and I have some ring products. I've already decided to get the ring alarm. My question is this: do I get the retrofit kit or start from scratch? I'm that I may only have one wired sensor (not sure) and I understand the wireless ones from my old system won't work. Nor will the fire alarm piece. So why should I even bother? But what if I start from scratch and ignore my old wired system -- how do I shut it down and deal with the old wires, etc? I'm not a do-it-yourselfer - I read about how to actually shut the alarm down, but what about all of the wiring. How do I deal? Electrician?