At present the NGI/EGI ecosystem is working to complete the transit from the project based funding to a set of sustainable governance, operation and funding structures to support long term success. This is an important but complex process and has been the subject of considerable discussion at previous EGI events. Despite hard work most NGIs have found it challenging to find new structures that are effective, achievable and will be supported by their national authorities. One reason for this is that sustainability requires a set of preconditions relatively well accepted in the commercial sector but more difficult for academic institutions. These include clear definitions of 'customers', service portfolios and catalogues, business models and IT Service Management processes. This presentation will introduce these factors and discuss how tacking them will facilitate work on sustainability.