Is there a rule when the props should be changed? (eg. 100 flights, 20 hours, etc.) I know it depends a lot on what modes are being used (eg. sport mode wears them off faster) but based on your experience, when should it be changed? Thanks!

Hello there Hrodnand. Good day and thank you for reaching out. Just a reminder that before each flight, it is necessary to check your DJI Air 2S propellers for cracks, wear, warp, corrosion, and loose screws. If any of these conditions are present, the propellers should be replaced. Damaged propellers can lead to unwanted incident when flying your DJI Drone. Thank you and fly safe always.

When they are worn off... if you take off/land from the ground instead of the hand or a nice surface like a clean table they'll wear off before (grass trimming, dust, little pebbles, etc).

Visually if there's any crack you must change them, but you can also pass your fingertips through the blades and if you feel there's any noticeable crack compared to a new one you should also change them. If they wear off to the point the motors have to increase the RPMs too much the app will tell you.

Don't know the exact flightime because I also fly the Mini 2 but I've flown more than 100 hours with the Air2S and are still like new, just clened them a liitle bit, never had a collision/trimmed the grass or hit anything solid.

Huginn Kenningar Posted at 8-12 01:31
When they are worn off... if you take off/land from the ground instead of the hand or a nice surface like a clean table they'll wear off before (grass trimming, dust, little pebbles, etc).

Visually if there's any crack you must change them, but you can also pass your fingertips through the blades and if you feel there's any noticeable crack compared to a new one you should also change them. If they wear off to the point the motors have to increase the RPMs too much the app will tell you.

Couldn't have said it better.  

Bottom line - visual and feel inspection will dictate when to change props.  

DJI once said 200 hours for props with an inspection on each flight.   I would add that if you start seeing wind warning when its not windy or ESC force errors/speed errors you may have sightly warped props that are not working efficiently but visually its very hard to tell.

After a few runins with the local flora I changed all my blades. The Mini 2 was so much more quiet, no more the half the noise. The old ones were either smooth or had tiny nicks. Some, the leading edge tip had worn off from just being used. New blades are definitely a huge improvement.