Recommendations for Private Private Keys

I am just starting to use RSA keys in my daily work, and I have a few questions regarding the best ways to use them.

The biggest question is about the idea of ​​multiple clients and multiple servers. Here is the scenario:

I have two client computers:

• Desktop
• A laptop

And there are two servers that I will authenticate:

• My own local server
• Remote service (e.g. Github)

So, as a rule, how many key pairs would you recommend in this situation?

• One pair of keys: this key is "I", and I use it everywhere.
• One for each client: this key is “This Client”, and I put it on every server that I want to connect to from this client.
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• : - .

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