I knew that "modern Trek" was getting long in the tooth when I was watching episodes of ENT and could think of at least two episodes of different Trek series that had used the same basic plot.
On the subject of direct remakes being made within the same series over the course of years, it reminds me of a phenomenon that I've read used to happen in comics back in the 50s and 60s. Members of the Legion of Super-Heroes such as Mon-El, Star Boy, and Sun Boy were introduced in Superboy stories that were thinly-veiled remakes of Superman or Superboy stories that had only been published around 5 years earlier. The belief in the industry at the time was that kids outgrew comics and the then-current readers wouldn't have seen the earlier versions of the stories.
And Charles Maxwell, who played Virgil Earp in "Spectre of the Gun," was in more Gilligan episodes than anyone but the seven leads
Were there seven leads...or were there five leads "and all the rest"...?