If you are an NRI living in the US and are going to India for wedding, DO NOT forget to get your marriage certificate along with you when you are coming back. I do not know how it works out or is required in other countries, but in US, especially if you are in the GC process or will likely be, you will soon realize that it is one of the most critical documents required.
Neither me nor my husband had any idea that we need to take a marriage certificate after the wedding. My mother was the first person to tell it to us and she was very persistent..she reminded each day until we went to the local registrar's office and got it.
It took us about 4 hours to wait for the document, but it was all worth it.
I recently talked to a friend of mine whose GC went into inquiry because of missing marriage certificate. Of course she also did not have her birth certificate and submitted a non availability certificate for it. She struggled through quite a bit to submit subtitutes...and finally got through later.