This is a general question that may apply to many people.
I have a web server that I use for testing. I recently added a Lets Encrypt SSL certificate with Certbot. I routinely wipe this server and start over. After my next server wipe will I need a new certificate? If not how do I keep my old certificate?
That depends entirely on HOW you use the certificate.
For standard web services, you can easily replace it with another.
So wiping (with complete destruction) will not matter much - you should be able to get another cert.
[limits permitting]