This is not making so much sense to me. If you buy a saw with an extra chain and the chain cost you an extra $22. You use the saw and chain over a weekend so now you have two chains that need sharpening. You take the chains to a shop for sharpening you spend an hour driving to the shop and $14 and then another hour to pick them up. So you have invested at least $50 in your two chains to cut wood the next week end. Add this times four times for each pair of chains and what is the cost for your chains. If you spend $200 on a chain grinder and a reel of chain it still would be much cheaper then taking your chain off and on to your saw shop. Or spend $300 on a reel of chain and files that will last you a life time if you are a weekend cutter. Anybody can learn to file a chain, but if you really can not invest two hours in to learning how to file a chain then maybe a grinder is the way to go. Of course there is no grinder that will sharpen a chain as sharp or last as long or as fast as getting out a file and clamp. Now if you have more than one saw it gets even more complicated. For me having at least three reels of chain and a hundred files and a clamp then I am set up with a dozen spare chains for every saw will last at least a few years of cutting a hundred cords a year. Thanks