If you are using headings (h1 to h6), you are already using something that could be called "implicit sections". The outlines of the following two markup examples semantically identical:
My cool site…
My cool article… …
Example 2:… … …
So in this very case it wouldn't matter if you explicitly add section or not: the outline (the semantic structure) would be the same. Side note: it is recommended to always explicitly use the sectioning elements for sectioning content:
Authors are also encouraged to explicitly wrap sections in elements of sectioning content, instead of relying on the implicit sections generated by having multiple headings in one element of sectioning content.
(however, this applies only for sectioning content, not sectioning roots (like body))
Now, your question can't be answered generally, if we don't know which headings you are using. There are cases which would require you to use section (or article), otherwise you would get a wrong outline for your page. And there are cases where the use of an explicit section (or article) is optional.
Some general tips (applicable to "prototypical" websites only; there are of course many exceptions; these tips should only give you an idea)