Hi all, I was just wondering what you consider an acceptable amount of lost steps when running your STEPPER based machines?

I have a cheepo X2 with a common cnc stepper based conversion ( 270 oz-in steppers) on ballscrews.

I am pretty sure I loose about .0005" to .0008". That is after about 340" of movement, about 11,000 lines of G-Code, running roughly 3-4 hours.
While that is not a lot of loss I will have to re-zero after each run.

SO HOW ABOUT YOU GUYS?
How much do you loose and after how much running of the machine?

Please, lets keep this thread on track.