Originally Posted by
Pharaoh
I was taught (by someone now fairly senior in the FAA) to write down every assigned frequency (scribble actually) on the corner of my clipboard.
I write down all frequencies (and usually all assigned headings and altitudes) as I get them. (I’m a GA pilot.) Also, “modern” GA radios let you enter a new frequency while still on the old, then push a button to switch to the new frequency. If no one answers, you can always push the button again to go back to the last frequency.