Email retention time


New Email
I have Windows 8. The retention time is set at 30 days, as advice is that a longer retention time would slow down substantially the loading of the Mail screen. The advice is to go to settings to see older email messages, but this does not saywhere these older emails are. The only apparent option in Settings is to leave all emails on the system, which would incur the consequent loading delays.
Is there an automatic depository for the email older than the 30 day setting, and if so where is it?
Is there a way to keep the 30 day setting to enable rapid screening, while at the same time have the folders without this limit i.e., progressively delete or transfer emails to folders and then manually delete items from folders when they are no longer required?