Best practice on deleting users?

[Michael Pokraka]

Hi all,
I'd like to know what you'd consider 'best practice' in deleting users and handling related workflows - and of course offer some of my thoughts.
One could for example lock an ID and forward WI's for a certain period - e.g. one month. What is an acceptable period / how useful do you find it? One site I worked at had orders that regularly ran over 5 years, so it didn't really help too much.
 
One reason I'm asking is that my current site has a tricky combinbation in that they a) don't use HR, b) delete users immediately upon leaving and c) are a heavy workflow user averaging around 60,000 WI's /day.
Even with the use of HR however, the situation remains where an agent is determined according to things like the creator of a document, a requisitioner, person who confirmed a T/O etc... all these are stored in a table and will thus at some point refer to users no longer in the system.
At the end of it we thus end up replacing nearly all of SAP functionality with custom methods, roles and attributes and spend a long time working out routing strategies and getting tangled up in 'what ifs' and 'but the Italians do it this way' and developing 'dynamic agent determination in case of failure' loops and just generally having fun patching 50-node workflows... should this all really be necessary?
 
Any thoughts would be appreciated.
Cheers
Mike