When interviewing for a new job, expect to have your references checked prior to getting a job offer. Plan ahead and compile a list of references and some letters of recommendation now, before you need them, so you are prepared when a prospective employer requests references.
One of the reasons that it's important to get references in advance is that letters of recommendation may be required as part of the supporting documents that need to be submitted with some job applications. Some employers are starting to check references prior to interviewing candidates rather than the other way around.
Recommendation Letter Samples