Robotic arm with stepper motor

[hans22]

I’m design 5 axis arm robot to

Pick and place
Sorting material
Sorting Color

it’s simulate the Sorting production line in factories and i need to make it do it repeatedly.
i’m using Stepper Motor 2 For the Joints of the arm the questions is do i need only Limit switch to each joint cause when the arm starting going to The Home Position and start their movements automatically, or i need encoder or pots in each joint with the limit switches to do this?