You still have to define "redundant". If you properly normalize addresses (something almost no one does), then each street should have one and only one entry in the database. However, five guys with the first name of "John" should probably not have that abstracted away into a single entry. Just because the data looks the same does not mean that it's the same thing.

Further, and this is a heresy that many database purists would be horrified by, there are times that DBAs will deliberately leave data denormalized for performance reasons (though this should not be done until you've gone down other avenues of correcting the problem).

We may be able to be more specific if you can describe at a higher level the problem you're trying to solve.