Auto transmition fluid replacement

YouTube's Scotty Kilmer reomends replacing the transmition fluid around 70,000, saying it gets worn out and needs replacement as a preventative measure.

My transmition is fine but is it a good idea to replace the fluid around this stage?

Many manufacturers will say it's "Filled for life" when it comes to gearbox oil, and that it doesn't need changed be it auto or manual. Or if you are more cynical then you'd think they know the gearbox will give out at somewhere over 100k miles and most owners will buy a new car. So it's not in their interest for you to look after the gearbox oil.

If it's a proper automatic with torque converter then it's not so simple to change, much of the fluid will live in the converter if you simply drain it.
Gearbox oil filled for life is marketing speak for, “filled for short life”, in order to sell you more replacement new vehicles. :(