What else should be replaced when replacing submersible pump?

[Atomic1]

Like the subject says, what other things should be replaced when replacing a submersible? I believe I have a poly drop pipe with a pitless adapter.

Does the drop pipe get replaced?
Oring on pitless?

 

[Valveman]

If the pipe and pitless look good, the o-ring in the pitless is probably the only thing needed to be replaced. But of course if it will fit I always add a flow inducer shroud to make the motor run cooler and last longer.