Painting question, should i paint parts separate or together...?

[OhioChevy]

Here is the way I am going to paint my truck. I will paint the inner fenders,
inside of the fenders, inside of doors, interior of cab, door jams, under the
hood, cowl and bottom of truck. Put everything together and then paint
the outside of truck. Like someone else has stated buy ALL of the paint that
you will need to paint the truck. I will paint the bed separate and then put
onto truck. Hope this helps.