For those of you that send and receive text/sms messages, I just wondered how quick you reply to them and does it depend on who they are from or what it's about etc? Also do you get frustrated if they take a while to reply or don't reply and if you do, does it depend on who you are waiting to hear from?

Some people seem to be quite different in this and what seems normal to one person, can be quite different to another which can cause the odd annoyance/frustration!