Macworld If your Mac is starting to run slow the first thing to check is if you are running low on space. It’s generally advised that you should have 10% of your total space free on your Mac for the most optimum working. If you are down to your last few gigabytes then it’s time to do some housework and grab yourself some space back. Over time, a Mac is likely to accumulate a large collection of duplicate files that take up this valuable space so that’s a good place to start. However, finding and deleting them can be time-consuming if you do it one by one, so in this article, we show you quicke…