On the techcommunity site a question was asked about how to reduce the risk of updates breaking your Office 365 SharePoint solutions
In the past too many times SharePoint has been broken by updates deployed by Microsoft. In recent months the new interface broken the global navigation leaving users with unable SharePoint solutions.
So what should SharePoint developers do in Office 365 to avoid systems breaking?
Try to implement SharePoint without any branding. Just use the theme options available.
Then when you get to the point of developing the solutions within SharePoint develop apps/Add-in/customizations instead of pages with web parts.
Add-ins are separate from SharePoint and use CSOM to talk to SharePoint and therefore SharePoint upgrades will not cause any issues.