When the covers of the chair wear out you tend to discard the chair. But instead of throwing it will be better that you design a new cover. There are lots of fabrics which are available in the market and so you can try designing from it. If left over pieces of cloth is there you can utilize that stuff for your cover. It will give you a unique look and will really work for a long time.
To prepare the cover, find out the dimensions and cut out the cloth in the same dimension. According to the shape you can stitch the cover with the design on the inner side. Then take out the inner portion out and your cover is ready to be used on the chair. In this way your chair gets a brilliant designed cover and no money is wasted in it. So this can be a cost effective solution for you.