How long a mail present in inbox

I'm happy to help! However, I need a bit more information from you. Could you please clarify what you mean by "how long a mail present in inbox"?

Are you asking:

1. How long has a specific email been in your inbox?
2. How long does an email typically stay in your inbox before you delete or archive it?
3. Something else entirely?

Please provide more context or clarify your question, and I'll do my best to assist you!