[SalesForce] Renaming custom object referenced in Apex class

The best solution would be to have an Event object and a many-to-many object (subscription?) which holds a lookup to the user and a lookup to the event. If an entry is in the subscription table then the user is subscribed to the event.

If you want to simply get metadata for the field, there are a few different pieces of information you can get.

Schema.SObjectField myCustomField = Credit_Insurance__c.Credit_Insurance_Status__c;
DescribeFieldResult describe = myCustomField.getDescribe();

If you want to get data, you need a Credit_Insurance__c record to get the data from.

Credit_Insurance__c record = new Credit_Insurance__c(); // instantiate as desired
String status1 = record.Credit_Insurance_Status__c;
String status2 = (String)record.get(myCustomField));
String status3 = (String)record.get('Credit_Insurance_Status__c');

With a checkbox, it would be:

if (record.Validation1__c) { /* do stuff */ }