Perod of responsibility for benefits of outcome and benefits

In general it is zero, until unless it is possible to realize some of the benefit in program duration and specifically defined as part of program managers responsibility.
Mosty benefits are realized after the program is over, as benefits depends on the outcome/solution provided by the program and hence out of the scope of program.
But a good transition is a must. I would agree from Kiron on this part.

The responsibility lies with program manager is to ensure that during execution of program it is ensured that the benefits are realizable as an outcome, if not he or she much raise the red flag. But may not held responsible for realizing it.

You might like to have a look at Prince2 method, which defines the execution with key focus on benefit realization.

-Tarun

Dear Thomas
Thanks for your inputs .
I agree theortically and may be contractually it is zero.
But In industrial engineering program in spite ,specially when the programs are run within the organisation and supplier remains one department like project or program department, it so happens that the customer {internal-plant heads or users) keep expecting the assistance as the sustainment goes much beyond program completion inspite of clear initial definition of Program completion. To that extent this remains an area abstract in nature due to humans involved as internal stakeholders/
Thanks and regards
Mohan

Zero.
If the program is over, the program manager is gone.

It is good practice to have a transition, which includes handover of the responsibility for benefits delivery (often from program manager to operations manager) and also a system to measure this.

Some programs continue until all expected benefits are delivered.

Not all solutions deliver benefits, some are just enablers for other benefits (like a new ERP system that enables users to be more efficient).

Zero.
If the program is over, the program manager is gone.

It is good practice to have a transition, which includes handover of the responsibility for benefits delivery (often from program manager to operations manager) and also a system to measure this.

Some programs continue until all expected benefits are delivered.

Not all solutions deliver benefits, some are just enablers for other benefits (like a new ERP system that enables users to be more efficient).