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It depends on whether or not an element can have an expanded octet. Some elements can only have eight electron so formal charge does not matter because you can't add electrons (however, you might be able to go to a double or triple bond), while others can improve their formal charge (closer to zero) by expanding their octet or increasing the number of bonds.
I believe formal charge is more important since, if its an ion, the formal charges of your Lewis structures have to match the ionization of the molecule. Also, when making your Lewis structure, you usually want a structure with a minimal amount of total charge. This means that the formal charge affects the structure, and the structure determines the molecular shape.
The formal charge is the best way to ensure your lewis structure is in the most stable state and to find its molecular shape via VSPER. Some ions may throw people off so formal charges are the best way to check your work.
It is better to follow and determine molecular structures base on the formal charger as there are exceptions to the octet rule. Formal charge is the best way to make sure the Lewis structure is in the most stable state it can be as well as writing out the right Lewis structure since the formal charge of the atoms must add up to the formal charge of the overall molecule.
If an element is in row 3+ then it can have an expanded octet. However, formal charge is still important because it makes sure your lewis structure is in its most stable form, making it easier for you to identify the shape of the molecule.
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