A good principle in SEO and SEM is don’t fix what ain’t broken.
We may hate that long, unwieldy page title, find a broad match keyword that beats goal yet covering too much, or feel some aspect of our digital marketing would do even better if we tweak it.
When you adjust on-page SEO, Google will adjust too. A new title could make the page less relevant to important searches, or Google determines the CTR will change so tests it for different positions. Customers also may not appreciate the change like you do as a savvy marketer.
Replacing PPC ads or keywords restarts the data-gathering process for optimizing conversions.
Don’t change what already works, or you may wish you had never changed a thing in the first place.