The tradition of "something old, something new, something
borrowed, something blue" has been around for hundreds of years.
Many brides have been asked on their respective wedding days if
they have gathered something old, new, borrowed and blue to carry
with them as they walk down the aisle. The tradition of carrying or
wearing one of each item is said to bring luck and fortune to the
newly married couple.

Something new...
Wearing something new is supposed to represent success and hope in
the bride's new life and in her marriage. If the bride purchased
her wedding dress new, it may represent her new item, but any item
that is new may be used. Something ‘new' is usually the
easiest category to fill.