"It's a way of showing their appreciation for the longevity of the relationship," she explained.
The publication observes an alternative motivation for a diamond ring upgrade - that partners may not share jewellery tastes.
Women given a wedding band that does not quite suit their style by their partner may wish to alter it, the news provider's Erin Hill states.
Brides-to-be may wish for a bigger gold diamond ring, or perhaps want to give their band an individualistic twist.
Meanwhile, Cameron Diaz's publicist has confirmed that a ring she was recently spotted wearing on her ring finger was not an engagement band, but a statement of her individual style.