In my mother's older years, she always kept a magnifying mirror on a stand ,on the kitchen table. When I asked why it was there, she said it was in a good sunny spot , and that she could check for facial hairs every day and tweeze them.
When she died I took the mirror, and it now sits on my balcony table where I have my morning coffee. In a nod to Mum, I also check for the hairs every morning in that sun which shows them up so well.
I'm always amazed at how there can be nothing on one day, and next day I'll find one which is half an inch long ! How does that happen ? It's one of the great mysteries of getting older.