Those who nowadays travel within the Eurozone can easily do without currency exchange offices.
Even strictest EU sceptics admit it.
Another benefit is that the common currency is accepted beyond the Eurozone.
Although in some cases one can even pay with euros, at any rate there is always a possibility to exchange the “euro-cash” to a local currency.
However, many currencies are not so flexible. For example, despite the favourable neighbourhood, one can hardly exchange the Belarusian ruble in Ukraine and Russia. The
Ukrainian hryvnia is also quite uneasy to exchange in many places.
A stark example for this fact is the "transnistrian ruble", a currency which can be used and changed only inside the borders of the not recogniced state of "Transnistria".
It is a common thing when one has to pay an especially high exchange fee for such “exotic” currencies; besides, in some offices a certain minimum sum should be produced for exchanging.
Try to avoid spending around a not potent foreign currency. Instead, use your credit card so that you show up with cash as rarely as possible.
Find out more about the exchange rate so that you have a better idea of pricing when shopping.
Exchange money with your friends that move towards the same destination – this way you both can save up money that would go for exchange fees.
Many charity boxes (for instance, at the airport) accept foreign currencies, so you can clear both your wallet and conscience.