Blocked drains? Environmentally and budget friendly advice from our plumber

Our house was built in the 1950's, so our plumbing is quite old. Throughout the year our drains block up, especially the shower drain (my husband blames my hair!). I asked our plumber for advice on clearing our drains. He said to throw away the commercial drain cleaners that you buy from the supermarket, as they only make the problem worse. They form a gel further down the pipes, which in turn causes more blockages. He suggested using bicarb soda and vinegar. Try sprinkling half a cup of bicard into your drains. Follow it with half a cup of vinegar and let it bubble for a while. When the bubbles subside, flush it out with boiling hot water (from the kettle). Repeat if necessary. This is best done from time to time to keep the drains clear rather than waiting for a blockage.