My particular age group was just a bit too young to watch TOS during first run, rather I caught it in the early 70s when it started to run on "local" channels. I'm in western Canada so local in this case was whenever a smaller affiliate stations in Seattle played it. Each time you watched a Trek broadcast back then you got a slightly different show, as it was cut more and more to allow for more commercial time. I swear some of them were only half an hour long when they were done!
So who decided on the cuts? Did the studios ever provide a shorter length edit to allow for the syndication? Or did each station have some intern cut out what they felt were "the less important bits"?
Is this handled differently today for the post TOS shows, where syndication is planned from the start?