How often is it desirable to send emails to the user about the status of his payment and the order itself?

Question

Electronic commerce

Self-written engine.
1) The user clicked on the checkout page "done, go to the Yandex/PayPal website for payment". There he can pay, and maybe change his mind. Send him an email immediately - "you have made an order, here is its content, payment status is pending"?
2) Paid. Let's say, as an admin, I received a confirmation in an hour. Send email "You see that your order is now confirmed".
3) We collect the order. Collected. We send. Send email "order left us"?
4) ......
Etc.
How often, what is recommended?

Answer 1

You choose the strategy and frequency of notifications yourself - aggressively or intelligently. If aggressively, then beat the user with notifications about each step. If intelligently, then this is how Amazon does it:
1. After placing an order:

Hello Vla,
Thank you for shopping with us. You ordered "Lodge Seasoned Cast Iron 5..." and 5 other items. We'll send a confirmation when your items ship. + order details + a block with products that are often bought with already purchased

2. After sending the order:

Hi Vla, your package will arrive: Monday, February 11. Tracking button + order details + block with goods that are often bought with already purchased

The scheme is relevant for a B2C site. For a B2B site, every order progress notification can be valuable.
If, after placing an order, payment for it is not received within the period you specified, then a trigger should work with a reminder of an abandoned cart and a motivator to place an order today. But this has nothing to do with the order notification chain.

Answer 2

3,
even collected -> sent out will be enough