Hi,
We mention in our instructions that you can roll twice a week the same skin area with a 0.5 mm roller:
https://http://dermaroller.owndoc.com/dermaroller-instructions.pdfI know that other sites encourage you to roll more often, but we think that their advice is based on medical ignorance or commercial motivations (they'll sell three times more rollers that way, as they blunt three times faster).
Rolling more often can be compared to bodybuilding the same muscles every few days. Instead of growing, the muscle will damage more and more, as it gets no time to repair the micro-damage done to it.
EDIT: If you are male with a thicker skin, you can roll three times a week with 0.5 mm. It also depends on where you roll. The skin on a man's back and buttocks is very thick.No, you can not sterilize anything with warm water alone. You would be seriously grossed out if you would be able to see the result under a microscope!
You would at least need a detergent to get rid of the skin oils. The recommended way is to put the roller in alcohol, as explained in our instructions.
Some people put them in the dishwasher, but we can't guarantee that the roller won't damage or blunt. Our manufacturer claims it's no problem.
Those cleaning tabs may blunt the needles. Those tabs are made to clean plastic, not metal. The tip of a needle is only a few molecules thick, so blunting can happen with acidic or alcalic chemicals, especially when using hot water.