What is evergreen content?
Evergreen content is always relevant, it is not time or date bound.
In the context of ConvertKit, our Sequences are designed to be evergreen. That means that anyone can sign up for your Sequence at any time, and two different subscribers would receive your emails in the same order, but on different days.
When you are getting ready to release a product, you can decide if you want it to be evergreen or not. If it's evergreen, anyone can purchase at anytime. If not, your cart would close, and there would be a "last day" for your subscribers to purchase.
Some advantages to creating evergreen content or products is that it's easy to manage. You don't have to worry about the logistics of time-sensitive promotions or cart-closings.
Some disadvantages to evergreen content is there is a decreased sense of urgency. Your subscribers may not feel compelled to buy right away because it is always available.