The key difference between a sewing machine and a serger is that all beginners will need a sewing machine. Beginners will want to sew fabric pieces together, create buttonholes, and add zippers to garments. These are tasks best accomplished with a basic sewing machine. Sergers cannot perform these basic sewing tasks. As experience is gained, some will want the extra capabilities and convenience that a serger offers for some tasks. Sewing stretchy fabrics is much easier with a serger. Hemming edges in a way that looks professional is much easier with a serger as well. It is possible to purchase an overlock foot attachment for a sewing machine. This will approximate a serger's capability, but will not be the same. A serger will give your overlock stitches durability that a sewing machine cannot. This is because a serger can use multiple threads. Sewing machines use only one thread. Both a sewing machine and a serger are helpful. If you have to choose just one, choose a sewing machine. When you reach the point at which a serger could make your work easier, invest in one to use alongside your sewing machine. Most who have the need for a serger cannot imagine going without one.