I got my model 3 last week and since then, my coworkers one by one would laugh at me about model 3 scooping up dirt because of this article
The Tesla Model 3 underbody is scooping up dirt and keeping it
Is this a problem for anyone? How would you react to that?
As with most things in the media, this issue is sensationalized and overblown. You have a Model 3, and it is very easy to check for dirt build up if you think it could be a problem for you (think sanded snow-covered roads for 3-5 months per year, or frequent dirt-road driving). You can also rinse some of it out by parking your car pointed downhill and washing the rear of the car. Or you can remove the frontmost section of the diffuser (remove 3-5 bolts), and just stick a hose up there. Annoying, but not a huge deal, and also not something most people need to even think about. If you have very muddy/dirty conditions, this is something (washing/flushing the underbody) you might need to do in many vehicles, not just a Model 3.
I would just make absolutely sure you have all your bolts (13 in the rear performance aero shield, 7+ in the rear diffuser), and then not worry about it if you are not in a high risk situation. Check out your car periodically when you wash it, or whatever - just like any car.
There are some separate threads here (search undercarriage, ripped, cover) detailing the potential issues with pictures.
But overall I don’t feel it is a big deal. Ensure all bolts are present, and don’t drive through standing water at speed. Be sane. Any car can be damaged with abuse, and every car has design flaws of one form or another.