Hi all! My question may sound strange and naive but this is sth I really can't understand. Reading about the Greeks I usually come across phrases like 'collecting theta', 'collecting delta' and so on. But what does that collecting mean practically? Say I've bought some credit spread and held it for 10 days. If it's theta was 0.18 - does that mean that I should collect 1.8 of theta altogether? If yes, how and in which moment I'll get this money as profits?