The invitation suite may not seem like the biggest part of your day, you may not even care for your invitation suite too much. It does play a huge part in your day by setting the tone for your entire wedding. Especially, the detail photos. They add all the details together. It's the connecting piece that sets the flow for the day!
Using a similar element in detail shots creates a cohesive flow that you cannot get, in my opinion, if you don't use the invitation suite. Usually, I use the invitation suite to get detail shots of it, earrings, rings, cuff links, etc. It makes a WORLD of difference!
