I have found that many travelers write down their expenses while on a trip. I always however found it difficult personally, because there are so many situation in which I do not have enough time to jot it down, such as paying for the cab and then rushing forward. So I get lost pretty quickly.
How do you deal with documenting expenses? Do you always do it after the payment or rather put together in the evening? Do you write down every single expense or just the major ones?
My main concern is about expenses for which you do not receive a receipt, like for example paying on a market or car pooling.