When I edit or modify my website, say improving or optimizing content, how quickly shoud I expect to see the results from those edits?
When you are modifying your site for SEO purposes, you should know here are multiple layers of obfuscation that go into action with significant site edits. These are patented processes that are meant to prevent keen blackhat practitioners from pouncing on singular tactics to increase rankings.
https://www.seobythesea.com/2012/08/google-rank-modifying-spammers-patent/
Your page is internally given an new internal ranking, but it will proceed to increase/decrease it’s rankings for your set of relevant terms and phrases over time until it generally meets that new position. The duration and depth of these fluctations, from personal experience and several case studies, can vary from industry and type of content.