Updated Landing Pages – when will QS change?

I just updated my landing pages for my Google Adwords campaigns. Actually I just created Landing pages since I made the common mistake leading visitors into the front page of my website before.
As I understand the QS is determined by several factors such as the content on the landing page, so I splitted my Ad groups and made sure that the target keyword exist in title + headings on the landing page. So far, so good!
Now I am wondering: When will this trick be affected on my QS score? They are not affected and still contain a few "great" and "poor" together with a lot of "OK". Which time frame should I expect here to see some updates on the QS? Or should I simply break down the campaign and start all over?

See original post by Zmags_JD