How long do you give a page before changing your SEO strategy?

I do changes from 14 days to 21 days. usually in this time period google notice everything which was changed

blueparrot said:

I usually wait and watch first. If the page is still not improving, then I update the content or build some links.

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Here too, I would prefer to let the data indicate the problem, and change anything accrdingly. Once enough time has passed, and it is still flat, then I would first test the content, followed by links if required.