There are a number of continuity issues around the Petries' homes. In "Fifty Two Forty Five or Work", Laura is pregnant, and the couple has just moved into the New Rochelle house. But in Where Did I Come From?", Rob and Laura depart from their old house to the hospital for Richie's birth. Then in "That's My Boy??", they come home from the hospital to the new house, in New Rochelle.
In "Hustling the Hustler", we see a nicely decorated basement in the Petries' home, with a pool table in it. But in this flashback episode, we see them buying their New Rochelle house -- and it has a giant boulder in the basement. In addition, it's stated that the Helpers' house is a mirror image of the Petries' -- but that's not the case, as shown in numerous episodes that feature the Helper home.
Rob: “Three hundred dollars? I ought to be able to get a better friend than Jerry for that!”