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It is strongly recommended that InCommon SPs and IdPs refresh and verify metadata at least daily. The security implications of metadata refresh are discussed called out on the Metadata Consumption wiki page:
Regular metadata refresh protects users against spoofing and phishing, and is a necessary precaution in the event of key compromise. Failure to refresh metadata exposes you, your users, and other Federation participants to unnecessary risk.
If you verify the digital signature on InCommon metadata (as you should), then the above implementation plan will affect your metadata refresh process.