Static vs Non-static Methods

Is there a reason Dynamo suggests having static methods? Are there any issues that should be known when using non-static methods. Say you had a class (let’s call it a Car) that has a public integer property called value, would it be more correct to define a method to increment it’s value as:

a) public static void increment(Car C)
{
C.value = C.value + 1;
}

b) public void increment()
{
value = value + 1;
}

Both seem to work, but was curious if there is any difference?