Leaky air ride

[panelman]

Hi all, I bought a passat off ebay- silly impulse purchase maybe, misses defiantly thinks so...
From searches, it was 'RobC' on here, with a build thread.

The previous owner 'checked it over' before I collected, and found the driver window motor had died, so knocked off a nice chunk of $$$ off.

The cars a bit tired, so trying to decide what to do with it- eg, fix, or break for parts.

The main issue is the air systems leaking. When parked the front will drop itself over time, and when I run the compressor it takes about 20mins to fill (as assuming leaking).

Wheres a good place to start looking for leaks, or is it just a case of feeling / soapy water around parts?

For other people with air- whats a normal amount of lifts per tank? I get a full lift, then a couple of small lifts, then its empty.

The car for people interested: http://www.ebay.co.uk/itm/Passat-V5-Est ... 3cfc24210f