Filter And Plug Wrenches Available here. One of the primary reasons most drivers don't do their own oil filter and plug replacements and maintenance is that they don't own filter and plug wrenches. Your oil filter removes grit from engine oil, and it should usually be replaced every time you change your oil. Since that happens every 6-12 months, you see those oil change bills adding up relatively quickly. With these tools, this routine maintenance is surprisingly simple to perform at home. Because of the differences between auto manufacturers, you have nearly unlimited options when it comes to automotive wrench shapes and sizes. However, one set of filter and plug wrenches should cover most all of your needs, even if you end up changing vehicles.