Having a shop sharpen with a chain grinder is easy but costly if you do much wood cutting. Figure the money and time spent to and from the shop (and dinking with them) when you could be cutting wood. But if you're a do it yourselfer and have much wood cutting in your future I suggest this: https://www.walmart.com/ip/Genuine-O...736A/116737374

I've used an Oregon bar mounted file guide like this for 35 years, countless hundreds of chain sharpenings to cut thousands of trees. It's a little work to use but superior to simply using a hand file and file guide to get consistent angles and depths. Accurate chain sharpening will give better performance and longer chain and chain saw life.

I also use a chain grinder to reform old worn, uneven and rocked chains. One like this: http://www.northerntool.com/shop/too...3874_200673874 Works great but not for everyday maintenance. The shops use chain grinders like this, and they sell more new chains because of it.