Transmission Flush

Hello FOAB's,

I've been reading a lot of mixed reviews on Transmission Flushes on classic cars. Some say that if it hasn't been done regularly that your in for some issues. Some say that to just drop the pan, drain the oil and change the filter and your good to go.... I got a 65 and don't believe it's upkeep was the every 30k recommended. Any experiences folks to stay away from this?