Did you ever get a call from a user or partner that they cant access Salesforce and it must be down? Before you log that case with Salesforce support, you have an easy way to go online and check the status of the Salesforce Orgs. You definitely should trust Salesforce.com as they post the status of the instances for the entire world to see.
The hyperlink is : https://trust.salesforce.com/en/
Once you clicked on Status above, you will get all the instances in your region.