As for keeping on the server, it's a setting in the client. In K9, for example, Settings > Account Settings > Fetching Mail > When I delete a message.
K9 only provides "delete" or "don't delete" options. Outlook has "delete after X days", but I assume others must as well.
As for keeping on the server, it's a setting in the client. In K9, for example, Settings > Account Settings > Fetching Mail > When I delete a message.
K9 only provides "delete" or "don't delete" options. Outlook has "delete after X days", but I assume others must as well.