Your Evergreen Newsletter Sequence is a Bonsai Tree
My experience is that people tend to take things literally, want to do too much, and think in binary terms by default.
I'm a big fan of evergreen newsletter sequences that line up a series of emails that get sent to your email list once a week when they subscribe to your newsletter.
The mechanics are simple enough. It's usually fairly simple to get started if you've written articles or sent broadcast emails.
Once approach I love is gathering a catalog of existing work and consolidating it into a workspace like Paper or Notion. It can be helpful to categorize the writing based on subject matter or themes so that you can clump together related topics.
After the work is gathered, you can remix it into something that is more "evergreen" by removing temporal language (language related to time) and present the topic in a stand alone fashion.
Unless you primarily write about current events or trends, this is usually possible!
One mistaken line of thought that I've seen regularly is that people won't want to receive what's already been published to your blog or newsletter. There's really only one word for this:
Guess what? Nobody is sifting through your back catalog waiting to pounce if you recycle some work. If anybody was doing this, they aren't likely to care if you recycle the work anyway because if they are going that deep they are in some sort of "super fan" category to begin with.
You don't need to take elaborate measures to ensure that nobody is seeing repeats. It doesn't matter that much and the people that get to see your work for the first time are the ones that benefit here so let's focus on them and not the one or two assholes you'll meet along the way that complain about your publishing process.
It's also worth noting that your evergreen sequence doesn't need to contain every email or post you've ever written. Pick out some good ones. Narrow it down to your favorite writing that will be relevant to your community audience.
An evergreen newsletter sequence is doing your community a service and sharing your research and knowledge more broadly.
Don't have a newsletter? I highly recommend ConvertKit!