Can anyone give a quick quide to the difference between Arrivals and Departure lounges. I have read a number of previous posts and also in the Ultimate BA Guide, but got bit confused and cant find a definitive answer.
ie
What is the primary purpose for the two?
Where are they located (landside/airside)?
Entry rules: ie Can you get into a departure lounge if you have just arrived on a flight in J, but your onward sector is only Y?
On average, which tends to be prefereable?
Any other handy tips/useful knowledge?

Maybe a fettled version of the answers can find its way into the Lounges link within the Ultimate BA Guide?