I plan on taking care of my wood stove efficiency with brand new stove pipe and chimney pipe. Getting new stove pipe and chimney pipe will allow the wood stove to work much more efficiently thus lowering my heating bills and giving us comfort through the cold winter.
After I do this I may change my in laws gas stove vent pipe and my masonry fireplace chimney liners. This will be a good bit of work but we will enjoy the benefits for years to come. I think the chimney liners will be the most difficult to do but I have a friend that is good with fireplace and heating work.
You should also think about doing the same for your heating appliances before the winter sets in!