When does Adwords re-evaluate page quality?
Adword does not really say. They are dancing around the subject like a hot fire but do not give dates or time lines when they well check your landing page next time.
They do not even give you guidance on how actually you should do to improve it just vague hints to have privacy and about us pages.
If you want to follow Adwords guidelines just click on the link.
They also say that some websites will always have a low score because of the nature of the website. But it is my guess as well as yours if that mean bad grammas, sex, gambling, or just ugly layout.
For more information check Adword help center
