A good rule of thumb is to not throw away your old negatives or slides until you are absolutely sure that the quality of the digital copies meets your requirements. Being able to scan your negatives at the highest resolution possible may give you some peace of mind when deciding to throw out the negatives.
Is there any reason to keep film negatives?
Film negatives are to photography what HD is to television. Sharper, richer, better. A new print made from a clean, well-preserved negative will produce a much sharper, better image than a print made from a digital scan of a photo. The negative is the 1st generation version of the image seen by the eye.
Is it necessary to keep photo negatives?
We recommend storing film formats in a plastic preserver like Print File. The Library of Congress has a good online document for the handling of photographs and negatives. In the grand scheme of life, slides and negatives are the keepers of stories and history. Stored properly, they will outlast any digital format.