This depends on how large the reservoir is, but a borehole is an asset that should last 50-100 years plus, with very low maintenance costs in the first 10-15 years. But for this to happen, you need to make the right decisions at the start of the process and invest wisely for long-term returns.
Each borehole will have its own characteristics. Boreholes that are only meters apart can have completely different water levels and delivery capabilities. But, if you and your neighbour are pumping from the same aquifer, over-pumping your hole could cause their hole to dry up