I am still tending to do a lot of indoor flights and in the clutter of my house the odd prop contact seems inevitable. Yes I know I could or perhaps should use the guards but....... Anyhow, I would say I have checked thevprops reasonably carefully after a contact but I have twice been caught out and subsequently spotted 'substantial' but almost invisible-to-the-eye cracks in the props.

For clarity I am putting these cracks down to contact damage and nothing else.

I do really mean the cracks were invisible unless they happened to catch the light at the correct angle, even after spotting one I could look straight on at the prop and, knowing the crack was there, still barely see it.

The drone had been flown with these props and there were no quirks or problems.
So dig out the magnifying glass folks especially if you now wear glasses.

Good tip!
Props look paper thin and paper rigid...I already had to change rear ones, they were probably flattened in FMC case.

Hello there Sean. Thank you for reaching out and for sharing these information with us. Please try to inspect the propellers of your DJI Mavic Mini regularly and each and every flight. If the propeller is scratched, cracked, bent, or damaged please replace them immediately for flight safety purposes. In addition, please try using the the DJI Mavic Mini 360° Propeller Guard when flying indoors. This propeller guard can fully protects the propellers of the said drone and improves flight safety, especially for beginners, or when flying indoors or in locations with many obstacles. Thank you and fly safe always.