Reason to keep expired passport?

Question

My passport expired in '07. And I haven't used it.

Answer 1

When you apply for a visa, many embassies will ask you for your previous passports to confirm you prior travel and prior visas held.  I advise you to keep your old passport(s) in a safe place for future reference.

Answer 2

You may need the expired passport to show them to the government when applying for a new one or when renewing later ones.(quite possible). Otherwise, it may get harder.(i-e: you may be questioned or have to fill more paperworks)

Answer 3

Records of previous travels are in the expired passport for future references which might be important if needed.

Answer 4

You can get your expired passport renewed.  It's easier and faster than applying all over again for a passport if you should ever want to.  Also keep it for identification purposes.