Sanford and Son was made from 1972-1977, and aired during these seasons, beginning in January, 1972. The episodes in the 6th season are from 1976-77, and were the final season in the series, although the cast were not aware of this at the time. Some of these episodes are very funny and have the typical Redd Foxx/Demond Wilson give and take, quarreling father/son chemistry, but some are not as funny, and less spontaneous.
First gripe: I find Fred Sanford's constant insults of his sister in law, Esther Anderson (LeWanda Page) to become monotonous and over the top, and too much to be funny. Sanford could have done one or two insults, but in some episodes, there are so many insult remarks made one after another, it doesn't seem funny and becomes rather dry, plus bogs down the flow of the episode. Sometimes LESS IS MORE.
Second gripe: "The Hawaiian Connection" seems odd, as it tries to incorporate a "Hawaii 5-0" theme into Sanford and Son, and it doesn't quite work. Somehow, Redd Foxx's junkyard humor doesn't cut it on a vacation in tropical Hawaii.
Really, this is mostly high quality, and of the same caliber as the earlier episodes, but some of the acting seems less inspired and spontaneous, and like some of the "magic" of the first 4 seasons is missing. You may disagree, but this is what I found with repeated viewings. Still, it is worth having, along with the earlier seasons.