After the series ended, Norman Fell and Audra Lindley made one last appearance on Three's Company (1976) during the episode "Night of the Ropers".
Jeffrey Tambor later appeared in three episodes of "Three's Company" in seasons 5, 6 and 7 but as different characters.
When the network proposed the spin-off of Three's Company (1976) (i.e. that they should remake the UK series George & Mildred (1976), which was the spin-off from Man About the House (1973)) focusing on the Ropers, Audra Lindley was excited and wanted to go ahead, but Norman Fell wasn't too keen on the idea. Fell felt that you couldn't do a series with *only* the running gag of Mrs. Roper being undersexed. The network assured him the show would have more substance than that, and furthermore, if the show didn't make it a full season, he and Audra could come back full time to Three's Company as the Ropers. So it was after six months of convincing, Norman Fell finally gave in. The Ropers (1979) made it a season and a half before it was canceled, As a result, ABC Network was not obligated to take them back to Three's Company, because their contract had passed the one year mark, so Norman Fell and Audra Lindley were out of work. However, despite their hard feelings they did reprise their roles as guest stars on Three's Company as Mr and Mrs Roper one last time before their characters were retired for good.
Based on the 1970s British sitcom, George & Mildred (1976) which itself was a spin off from Man About the House (1973).
According to his interview with the Archive of American Television, Jeffrey Tambor's salary was $6,000 per episode.