  The galactic microquasar GRS 1915+105 has been in a continuous state of
outburst since 1992, over 20 times longer than any other black hole X-ray
transient. Assuming that the outburst is powered via accretion of an irradiated
gaseous disc, we calculate how the predicted outburst duration varies according
to the efficiency of the self-irradiation mechanism. At least one current model
leads to the conclusion that the end of the outburst is imminent. The timing of
the decline of GRS 1915+105, whenever it arrives, will be an excellent
discriminator of the self-irradiation mechanism in X-ray transients, allowing
us to infer the fraction of the disc that is heated by the incident X-rays and
the magnitude of the mass loss rate in the form of a wind.
