Two of four nylon screws twisted apart as I was attaching my new license plates to my car, so I had to drill out the broken parts (which wasn’t too difficult since the nylon is essentially plastic). For awhile I regretted my decision to use nylon screws. Until I read about someone who had metal screws break off.
Still, I probably need to go get more screws because I had to finish the job by using some other screws I had laying around, the result of which is that each of my license plates has two different screws, and that looks kind of chaotic to me. On the other hand I may decide to leave well enough alone.