In my experience, it's quite rare for TM1 customers to successfully take over their own TM1 development once the initial solution has been designed.
In the sales phase, we often pledge to train the customer and handover the work but once the project commences, this pledge is often forgotten.
As consultants, there are plenty of things we can do to make our models easier to hand over and self-maintain, but generally we are not incentivised to create truly maintainable and extendible models.
It's not that we don't want to, or we want to create further work for ourselves -- although I'm sure this does happen in some cases -- but most projects are too hectic to allow the time for it, and customers are usually unwilling to invest the additional time and money required for such an intangible benefit.
How successful have you been in handing over a solution to customers so that they can maintain their own system?
Flow OLAP -- We think outside the cube!