Which statement is correct about atribute selection in predictive modeling?

$1.$

There are two approaches: The manual $($user discards IVs$)$ and the automatic $($using attribute selection methods$).$

$2.$

Attribute selection is always a mandatory data mining step.

$3.$

Automatic attribute selection is safe and should not be double checked by the user, after its completion.

$4.$

Manual attribute selection should be avoided because it is cumbersome.