If there are 180 total guests being invited, then the couple may only need 100 to 140 invitations. Always order a few extra invitations in case the couple realizes they forgot to add someone to the list. Also order extra envelopes in case mistakes are made when addressing the invites.
Making the right choice _ There is also no "right" choice when designing your wedding invitation. There is no one color that will look acceptable. Many people choose colors from their wedding theme to help coordinate the look of their wedding, but that is not necessary. It is more important that you choose a look that you love. The wedding invitation is a lifelong keepsake of your special day.