To give your friends and family plenty of notice prior to your arrival or a time your due to meet them
Chap1: Alright mate, can you give me a rough PTA your arriving in town?
Chap 2: Parent Teacher Association?
Chap1: No you CLOWN!!! What time are you getting to town?
Chap2: Non responder
*few hours later, chap1 is in the shower*
Chap2: Just on the train now, I will be in town in around 45 minutes
Chap1: FFS chap I’ve just got out the shower you Clown. Thanks for giving plenty of notice