Duluth trading or Kuhl when I'm in plants and need something durable. Ralph Lauren Polo for business casual and More formal meetings. Polo golf shirts are the only golf shirts I've found that don't shrink and lose its shape. I have several that are 4-5 years old and still look decent enough for travel days.

Kuhl work pants are about the best I've found. They have just enough stretch in them to not bind when squatting, climbing etc. they are not cheap though. They are also pretty stain resistant.