How long are messages saved with Zoho and how much space is used if messages are Archived?

How long are messages saved with Zoho and how much space is used if messages are Archived?

I really have two questions. The first is how long are messages saved before the older ones are deleted (or is that just an issue if space is needed). The second question, if emails are archived, how much space is that worth and how long would those messages be kept?