The GBP1Bn terminal rebuild programme at MAN is expected to take around ten years from start to final completion. Work will also take place in modules, one section at a time, which means that progress could be paused quite easily during a major economic downturn.
These days, one billion spread over ten years is not an unmanageable sum for a business the size of MAG which is bringing in healthy profits at today's traffic levels. If you compare the MAN redevelopment price-tag with the proposed sums required for developments at LHR and LGW you will get a sense of perspective on this. By today's standards, the MAN costings are relatively benign. MAG can schedule repayments over a long period, and of course should enjoy increased business as a consequence of expanding capacity and improving the attractiveness of the facilities to operators (US pre-clearance, dualing of taxiways etc.). And of course, MAG has control over the rate of redevelopment module by module. If the economic climate turns nasty they can pause and reschedule the next module.