Hey Sherry McGuinn! I’m glad you liked it!
This is a tough question because (as I briefly mention in the article), if you have an extensive back catlogue of evergreen content, you may be able to monetize quicker than a newsletter, which delivers current and breaking news.
Generally though, readers need enough content to sample your publication before they will commit.
This can be structured as a long stretch of free posts (say, everyday for 2 months, at which point you make most posts going forward paid). Alternatively you could enable paid functionality relatively quickly, if you feel your audience is strong enough.
Remember though, free signups are all potential upsells, so if you can, I would post high quality content on a regular basis, for as long as you are able to maintain, before charging.
If you already have a large following then you can probably turn on paid posts quicker.