So many factors are important when applying for any type of immigration benefit that you should almost always consult with an attorney before you file an application, and before you call this a statement of self-interest made by an attorney, please read on.
Here are a few cases I have seen:
Scenario 1: John Doe is a USC and wants to marry his girlfriend, Jane, who lives in China. His girlfriend has a valid tourist visa to enter the U.S. and she comes to the U.S. on this visa. She tells the officer at the point of inspection that she is coming to visit a friend and plans to return to China. During her visit, she marries John and he files for her green card so she does not have to leave the U.S. After a long wait, they get an interview notice and attend the interview. The Officer accuses Jane of improperly gaining admission into the U.S. by using her tourist visa, when she really intended to marry John at the time of her entry. Jane is now inadmissible and her very simple application has become complicated.
Scenario 2: Jane Doe has filed for divorce and has met a special person, John, she now wants to marry. Jane is certain the divorce is final, but does not confirm this before she marries John. John needs a green card so Jane files a family petition for him. After Jane has filed the petition for John, she receives a court order in the mail saying her divorce is final. Jane notices the date of the divorce decree was effective after the date she married John. All of a sudden Jane discovers she was married to more than one person at the same time. Does this affect the application she filed for John? Yes.
Scenario 3: John Doe is a permanent resident and noticed that his green card is expiring. He needs to file a simple application to get a new card. John does not know that his prior criminal arrest and conviction will have an impact on his status in the U.S. and files his application. John goes to his biometric appointment and is taken into custody and placed into removal proceedings. John is unprepared and shocked by what has happened.
What these scenarios show is that what one may view as unimportant or insignificant, can really be important and significant. Therefore, even if you do not think you need to hire an attorney, consult with an immigration attorney before you file your application. An experienced immigration attorney will ask you the right questions and give you important and relevant information that can make the difference between whether you have a successful case or not.