Criteria also involves your visitors’ OS/browser profile support for Letsencrypt issued certificates. LE SSL certs don’t support WinXP < or > SP3, so if you have a sizable portion of WinXP visitors, then LE SSL certs might not be for you.
Then again other paid SSL certs may not support WinXP < SP3 as all SSL certs are sha256 based now
You can see this thread Which browsers and operating systems support Let's Encrypt as well as example of how I use Google Analytics to break down my OS and browser profiles for visitors to determine if a particular site of mine is suited to particular SSL certificates and/or ssl cipher preferences that include or exclude WinXP https://community.centminmod.com/posts/21440/.