I was reading through the documentation in salesforce for using a singleton pattern and it is mentioned.
Limiting Impact of Governor Limits - certain system objects and methods, such as Apex Describes, are subject to governor limits. The Singleton pattern allows repeated reference to these without breaching governor limits.
But I thought that limits around describe calls got removed in some earlier release. Is the documentation not updated? Or am I missing something?
Your link is to the Salesforce Developer Wiki which was retired in 2018. I would no longer treat that as documentation
Years ago, the Salesforce Developer Wiki was a trove of valuable technical resources but these days, there is a good part of those 1.6k pages that is now obsolete and duplicated by our documentation. We concluded that it was time to act for the sake of the quality and relevance of our technical resources.
It also has the following statement at the top to signify why/when it was created:
This is a wiki version of the Dreamforce 2012 presentation 'Apex Design Patterns'
Documentation now has the following url
developer.salesforce.com/docs/....
In terms of your question, the limits were removed in Summer '14 (pg. 274) so that wiki was created based on a presentation done before that occurred.
Limits for all Apex describe calls have been removed for all API versions.
Describe calls include describes for sObjects, fields, field sets, child relationships, picklists, and record types.
You’re no longer limited to describing 100 objects or to executing 100 describe statements
