[torrent-of-ions]

Low gear is best for acceleration and overall control, high gear best for cruising. So accelerate in 3rd (or 2nd if your car is fun) to cruising speed, put straight in 5th/6th and activate cruise control.

It's a waste of energy and clutch/gearbox actuation to use the in between gears and there's never anything wrong with being in a low gear at any point unless your engine hits the red line.

On most cars fourth gear is really for cruising at a lower speed than is comfortable (or safe) in fifth.

You can also very easily downshift sequentially through the gearbox. Downshifting through several gears takes much more practice to do properly and isn't very useful on the road.

[fnj]

I learned to tease my 4-speed automatic TDI into shifting from 2nd directly into 4th, by accelerating strongly to 40-50 and then abruptly lifting throttle.