Currency exchange can be a difficult jungle to negotiate.
You can buy Euros at a ‘no commission’ outlet in the UK, only to find that you have actually paid about 10% commission and then another 10% when you try to change back any remaining Euros.
Also, as a Senior Traveller, do you really want to be carrying around lots of cash?
So what is the answer? Well over the years I’ve tried lots of different approaches. My solutions, learnt by trial and error, can be found in: Travel Money.