You don't leave it there for 10 years you dimm fool. You buy it from one of the sheds, use it for a few minutes and then get your money back.
Read any interesting plumbing leaflets today?
Recent reports from Japan of all places say consumers are totally fed up with inadequacies of combi boilers and are now ripping them out and installing high efficiency superinsulated copper tanks with a condensing conventional boiler instead.
Copper tanks shiny and bright, What every fashionable airing cupboard is wearing this year and for many years to come.