Keep the User Guides.
If you believe that they take up too much space then move the User Guides to somewhere else but leave accessible.
Sometimes when there is a problem the details will matter and without the Guides there could be no other way to check things.
You may be able to go online and retrieve the Guides - may or may not be viable. Lenovo may discontinue the guides for older products. Or newer versions may not apply to your build.
Also, I would not rely on being able to get online.
Plus there are a number of online "manual" websites that often trip AV warnings, fake "you must call" notices etc.. Avoid.
My recommendation: simply collect all such guides and documents in a well-identified folder and save.
As a loose rule, I tend to print out a few of the key pages for hard copy reference.
When there is a problem, the information you need will likely be in the Guides.
Remember Mr. Murphy.