mail days to sync in ios 12.2

Does that mean your Inbox contains 0 email? Have you tried signing in to your mailbox with a web browser to check if it's really empty? Do you have other devices (computers, smartphones or tablets) that check the same mailbox?

> That's because according to another thing I read the number of days to sync was still in iOS 11, and was no longer in iOS 12.

That's not iOS dependent. It is mail server dependent. As far as I know, only Exchange server offers the number of days to sync. As for iOS versions, it is possible that iOS 12 mangled Exchange (ActiveSync) "Days to sync" feature but if your mail provider does not offer Exchange ActiveSync access, any iOS version will not offer "days to sync". That seems to be the case here because RoadRunner or Spectrum does not offer Exchange ActiveSync access.

If the ability to control mail days to sync is not located in Settings > Accounts & Passwords, whatever account you are using doesn't offer that ability. What kind of mail account is it exactly? Yahoo? Gmail? A work email account?

I'm on iOS 12.2 and with Exchange email accounts, I in fact do have Mail Days to Sync. Exhange email accounts offer this, where as other accounts may not.

Contact your ISP. This isn't an Apple issue.

Number of days to sync only available on Exchange mail server. I highly doubt Road Runner uses Exchange mail server.

What do you mean by saying "disappear" below?

The emails only disappear from my new iPad and a fairly new Kindle Fire. My 2010 iPad and 2007 Mac Mini keep the emails. My Chromebook has a Gmail account and keeps the emails

> I went to webmail as you suggested and sure enough only the last few most recent emails appeared.

So they are not deleted?

> My old iPad and my old Mac Mini are keeping all the emails I don't delete in local (device) memory.

Are they configured to access your mailboxes over IMAP?

> I see that what I have to do is either find a way for the new iPad to save emails to its own memory, or at least find a way of saving the emails I want to keep onto the device itself. I can always get a micro PC card if memory becomes a problem.

Forget about iPad storage limit for now. That isn't your problem. Find out how your mail accounts are configured on all the devices (IMAP? or POP?). Start from there.

If you are using an iCloud mail account, I do not believe that there is this option as it syncs everything by default. Please reply if you are not using an iCloud mail account.