A trip down memory lane
Recalling pleasant memories

In one ear and out the other
Forgetting something immediately after hearing it

Lose your train of thought
Forget what you were thinking or saying

Memory like a sieve
Having a very bad memory

Jog someone’s memory
Help someone to remember something

Stick in someone’s mind
Something that is easy to remember or difficult to forget

A mind like a steel trap
A sharp, quick, and excellent memory

Out of sight, out of mind
Something forgotten when not visible

Slip someone’s mind
Forget to do something

Bear in mind
To remember something

Rack your brain
Try hard to remember something

Commit something to memory
To intentionally memorize something

A photographic memory
The ability to remember things in great detail

A walk down memory lane
Nostalgically remembering the past

Refresh someone’s memory
Remind someone of something they have forgotten

At the back of your mind
Something you are aware of but not actively thinking about

Engraved in memory
Something that is impossible to forget

Blank out
To forget something completely

Etched in one’s memory
Something that is permanently remembered

Lose your memory
To forget things, often due to aging or trauma