But basically, you're looking for the setting Download Complete Item Including Attachments.I can't tell you how many times I see clients with thousands upon thousands (and in some cases tens of thousands) of emails in their Inbox.
Instead of just letting those Inbox folders grow to outrageous proportions, set up auto archiving so that your Inbox retains only a portion of those emails.
This can go a long way toward speeding up your Outlook experience because Outlook doesn't have to read its data file across a network.
Instead, all it has to do is read the locally stored data file.
Stellar and LMOD i Cal feeds do not currently set this value, which means updates may be limited to when Outlook performs a Send & Receive operation.
If your Outlook program is not set to automatically run Send & Receive periodically, you can adjust this interval in File Google Calendar does not allow you to adjust the update interval for i Cal calendar subscriptions, and does not observe a TTL set in the calendar feed.