Does the engagement ring become the wedding ring once vows are
exchanged after the wedding ceremony? Or, does the groom need to
purchase a whole new ring that the bride will wear once they are
married?  In other words, do I need to buy an engagement ring and a
wedding ring, or just one?

artielange,
Its generally accepted that an engagement ring and wedding ring are
separate items. The distinction between them is that the engagement
ring is the big dollar item (reflecting the value of any gem quality
stone incorporated into the design) used throughout a marriage at
special occasions etc, whereas the wedding ring is a more simpler band
of gold (or other material) that is worn for everyday use.

However this is only a guide and it is becoming more common (with
mutual agreement) to vary this arrangement based on your needs,
whether emotional or economic.

A few guides on etiquette that may be of some assistance:
http://www.supanet.com/ladiesroom/weddings/etiquette/need_rings.html
http://www.net-weddings.co.uk/Etiquette/etiquettemenu_rings.shtml
http://www.topweddinglinks.com/etiquette.html

Kind regards,
gfmaster

I don't know what the real answer is but for me, the engagement ring
that I gave my wife became a part of the wedding ring. She purchased a
simple white gold ring, welded it to the side of the engagement ring,
and called it her wedding ring.
I was glad I didn't have to buy another ring!



Ed.

I recall that my wife's engagement ring was very expensive; her
wedding ring less so.

She always wore both.

That's something you can work out with your bride-to-be.  Some women
don't want two rings.  I didn't.  I said just a wedding band for me,
thanks, and nothing to detract from it.  I didn't need a diamond.  My
husband gave me a diamond pendant when we'd been married about twenty
years, but I still wear only the wedding band on my finger, and I
never take it off.

I have a friend who said no ring, period.  She's been married for many
years, but she doesn't wear any kind of jewelry on her hands at all. 
And there's another who was given an enormous emerald on engagement
and still wears that as her only ring.

Where customs vary, you can make up your own.  

Archae0pteryx

I have seen married women wear one ring and I have seen married women
more commonly wear two rings.  However, I don't know if the women who
wear one ring got it before the ceremony.  Interesting question.  I'm
sorry I don't have a solid answer for you.

Ask her what her expectations are.  The notion of seperate rings is
really a product of the last century, fueled mainly by diamond
industry advertising.  On the other hand, you don't want to make the
woman you hope to spend the rest of your life with feel unappreciated
on her wedding day.  Hence, knowing her expectations is crucial.  I
know of some cases where an "intention of engagement" pearl ring
preceded both the engagment and wedding rings.

P.S.  Don't you love how the commercials even tell you how much to
spend on he ring. "...How else can you make two months salary last a
lifetime."