The support team have had a bizarre run of client broadband failures to deal with in the last two better chance of avoiding stress from some scenarios, but hosting email in the cloud takes care most common local issues.
On-premises email servers (such as Microsoft Exchange Server) is dependent on electricity, broadband line and the IT infrastructure all to be working to keep email flowing. If your Exchange Server is hosted in the cloud (with Office 365, for example), email will continue to flow to mobile phones or laptops with 3G access even if your servers and internet are down.