We bought the ls100 laser engraver with the extraction unit from gravograph about 2 years ago now,and we only clean the lens about every three months,we have had no problems with our machine apart from trying to clean out the dust bag as these are expensive to buy.We have found if you fill a bowl of hot water and soak the bag in it then put it through the washing machine it becomes reusable.Other than that no issues whatsoever,but our shoe repair machines are cleaned and emptied regularly.