The cost of COLOR film dramatically reduced between 1964 and 1966..so TV series switched to full color. Most series were shot on FILM back then vs videotape. So many series switched in 1966 to color..hence many series of the time have one season in B&W and the rest in color. (F troop, Lost in Space, etc) .   See 2 other replies

Quoting from the Wikipedia entry on Color Television: "Although introduced in the U.S. in 1953, only a few years after black-and-white televisions had been standardized there, high prices and lack of broadcast material greatly slowed its acceptance in the marketplace. Although the first colorcast being the Rose Parade occurred in January of that year, it was not until the late 1960s that color sets started selling in large numbers, due in some part to the introduction of GE's Porta-Color set in the Spring of 1966 along with the first all-color primetime season beginning that fall."That seems as plausible an explanation as any for the magic year of 1966. A great time to have been alive, eh?   See 2 other replies

True, but each is only 30 seconds making a total of 6 minutes for the whole hour. That's still fewer commercials than they had when it originally aired (7 minutes), and FAR fewer than today's show content. LIS ran 53 minutes. (They seem to have clipped off a minute for more commercials in the 3rd season). "Hour long" shows now-a-days only run 43 minutes now.I don't mind HULU's commercials as long as they don't split the segments any more than the show originally had and have commercial breaks no longer than one minutes.   See 1 other reply