Septuagesima and the following days are observed in Anglicanism and in some Lutheran groups. The Eastern Catholics and Orthodox of course observe pre-Lent.
(Hence my comment above about ecumenism. If the Anglicans could keep it…wouldn’t it have been ecumenical of us to give it a chance to live as well?)
The point being…Lent calls for preparation. And while it’s all well and good to look at the calendar, wonder, “Hey, when is Ash Wednesday this year?” And then say, “Yikes…that’s soon! Okay. Start thinking. What am I going to give up?” …well, what these traditional preparation-for-the-preparatory seasons do is to set the fact of that realization and need to prepare into a deep context that is wise, rooted in the richness of tradition , and helpful.