Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

What is the lifespan of a series of currency?
Currency lives no more then 50 years. US currency did not expire in last 100 years, but it was reinstated few times, last one was 2009. Note that currency is not just what you hold in your hand. Currency is system of relations of money supply (currency is not money but we forced to use standard terminology), banking rules and government policy. Currency exists as long as government wants it to. In 2009 for example, US government decided it needs new currency and just printed whole new money supply. So US dollar is now counting as "partially fresh new currency". It was reinstated. Not expired. But today's dollar is totally different from 90s and 00s. Will it be accepted after 200 years? Yes (probably). But most likely at that time there will be totally new US dollars. And new Euros, new Pounds and so on. Currency is method of transfer. You can have that physical coins you have, but as economic agent it will die very quickly. It is not only related to inflation, in fact, inflation is the least of your worries. If you count all currencies in the world which ever existed, most of them 99.99% are completely dead by now (with governments which supported it). Not even single one currency which lived more then 100 years. US dollar was reinstated in 1860, 1907, 1930, 1973, 1987, 2009 and  in fact it is not single currency but dozen which were allowed to be used "for compatibility reasons".