We recently purchase a 330i 2003- sport/premium. The car had 43,500
miles on it but looked pretty good. After I washed it, in my thorough
fashion, and waxed the oriental blue metallic paint, the car looked
wonderful.
The only exception is the number of paint small chips due to rock
impacts. None of the chips went to the metal but a white undercoat made
the chips very noticeable. I've lurked it the NG for awhile and this is
my first post. Some time past, I read someone saying, "ditch the
matchsticks and applicator brushes in the touch up paint bottle." Their
recommendation is to buy an appropriate, small tip, quality paint brush.
Yesterday, I went to a hobby store and bought a decent brush. It feels
good in your hands and has a tiny pointed brush.
I accomplished the touch up. The car looks great.

It's a numb skull post, I know. But I've owned a few cars in my time.
And I have been forced to touch up the paint chips. It's just amazing,
to me, how long I've struggled with all the different applicators but
never being satisfied with the result. I spent $3.00 on a brush that I
can re-use, and I'm happy.

Thank you for saying what should be obvious but sometimes it is not!
Some people need help to get a clue :-)