Changing SEO Strategy is an absolute because search engines themselves keep on changing.
1. Search Engine Algorithms
Search engines are known to modify and improve their algorithm. If the algorithm leans more towards the user or leans towards on link building, the SEO Strategy needs to be modified.
As search engines change, the behavior of users also changes from time to time. New trends or products can bring a big change in the SEO world.
Google Analytics interprets the performance of the website and your SEO, which will prompt you to make some decisions in between your SEO strategy.