Breakdown of Я заранее поменял валюту, потому что в аэропорту курс обычно хуже.
Questions & Answers about Я заранее поменял валюту, потому что в аэропорту курс обычно хуже.
Поменял is perfective, so it presents the exchange as a completed action: I exchanged it.
If you said менял, that would be imperfective and would usually suggest a process, repetition, or no emphasis on completion. In this sentence, the speaker means they took care of it beforehand, so the completed action is the important idea.
- Я заранее поменял валюту = I exchanged the currency in advance.
- Я заранее менял валюту would sound unusual here unless there were some special context.
In everyday Russian, поменять валюту often means to exchange money / currency.
Literally, поменять can mean to change or to swap, but with валюта or деньги in the right context, it commonly means to exchange money, for example at a bank or exchange office.
So here:
- поменял валюту = exchanged currency
- not just changed in a vague sense
A more explicit version could be:
- обменял валюту
- обменял деньги
But поменял валюту is very natural in speech.