Oscar's zodiac sign is Taurus, and Felix is a Pisces. These are the real-life zodiac signs of Jack Klugman and Tony Randall.
Mamie the tap dancer is the mother of Garry and Penny Marshall
There is a very rare fourth wall break in this Odd Couple episode. When Oscar calls out Walter Leonard Barr to tell Felix a few jokes (to convince Felix that growing older isn't so bad), after a few initial jokes, Barr then turns to the studio audience as he continues telling jokes.
The title is based on the expression, "Old soldiers never die, they just fade away" spoken by General of the Army Douglas MacArthur upon his retirement in 1951 in front of a joint session of Congress.
Mildred Fleener comes up again in the tag of episode 406: The New Car. The boys win a new car from Dick Clark for winning a radio contest about Opera. The episode was about the frustration of parking in New York. Felix says, " I will never forget the first time my folks let me take the car out by myself. My high school graduation. I tied a raccoon tail to the antenna. I took Mildred Fleener to the prom after the prom we went for triple pistachio sundaes. And we parked in the moonlight. She threw up all over the front seat. You think I was wrong not to kiss her good night?"