In a job application with the government they asked to e-mail them references but didn't specify what type (e.g. character or workplace). I was wondering what type of references are good to have? I normally keep on hand a few character references (organizers at volunteer work I do) and my manager of past jobs. How many references of each type should I give? How long is a reference valid for? For example I still have the contact information of jobs I worked at 8 years ago, and I doubt a manager who I didn't work closely with in the first place would be able to verify or deny a claim I made (for example would a manager really remember who setup the RAID on a particular computer 8 years ago?).
What kind of questions are asked when a prospective employer contacts a reference? How should a reference be asked/reminded/notified that you have/would like to use them as a reference? Also when giving references, any tips on the format and information to include on them? I started including a link to their linked in profile so it can be verified they work where I claim they do.
Out of curiosity why do some companies care more about references than others do? I've had some that don't check at all.