Technical requirements: B, V images down to a limiting magnitude of ( ) in at least 5-10 fields. Images repeated after 5 and 10 years for proper motions would be quite important.
Though the LF of the white dwarfs (WD) is relatively well known down to MV=14, there are a few open questions for the even fainter WDs which seem less in number than expected (Liebert et al 1979, 233, 226). This means that the cooling times could be shorter than current models predict.
A statistically significant LF of the WD will give information also on the stellar mass function. This would be particularly important for the halo WDs. Halo WD identification would give completely new information. Halo WDs are not presently detected because the present survey are in small fields or not deep enough. The number of halo WDs is important to establish they contribution to the halo dark matter.
WDs can be easily distiguished with the colors. But at the faintest magnitudes proper motions are necessary in order to distinguish the WDs from the background extragalactic blue objects.