what car, engine, trans, miles, color??????????
i have never had a problem with the crank seal.
if you plan on keeping the car a long time,
i would do everything.
i hate having to go things over.
if money is tight and you plan on getting rid of it ,
don't forget the o-ring for the oil pump
and to check the screws on the back side of the pump.
they can loosen up over time,
some years are worse than others.
and check for the leak on the rear of the block.
there is a plastic cover that can leak, badly.
at a glance you might thing it is the rear main seal,
but it is not.
the replacement cover is metal,
get the screws that go with it.