indeed!
We ordered a mosquito nets for upstairs (I am very afraid of another zyka-ridden summer), paid a deposit and the rest upon installation. They said they'd come on Thursday, so we exchanged on Thursday morning. Instead, they came on Friday afternoon and I was upset because we 'lost' money by exchanging when they had promised to deliver instead of when they actually did.
On another account, at the dietetica, we had a shopping galore, and the total was 12 USD!
Previously, I checked the exchange rate in the morning, only. Now I do it several times a day.