You should use the time element with the datetime attribute when you need to markup dates. For example, it's suitable for markup of publication date or day of the week.
Don't do it
<span>October 5</span> <span>two days ago</span> <span>a Saturday</span>
You can use it instead
<time datatime="2019-10-05">October 5</time> <time datatime="2019-01-29">two days ago</time> <time datatime="2019-09-23">a Saturday</time>
P.S: I share my experience with my Linkedin subscribers. Are you interested? Join to us! 👉 https://www.linkedin.com/in/melnik909/