A kukri can last a life time if properly used and looked after. This house has many examples of old kukris that has lasted more than centuries in its stores. To make a kukri last that long, one needs to always check what one is using it for. The target must not be harder than the kukri. Every time after use, one needs to wipe the kukri dry with cloth. Make sure no residue, no water or even finger prints are left on the kukri as it turns into rust within a few days time. Scratches and marks are likely to appear as you work with them. One can buff them up with buffing machine.
Apply machine oil, vegetable oil, silicon oil or any other lubricants on both side of the kukri to prevent it from rusting. Remember to oil it before you store it for longer period. Keep checking; if the oil has dried then re-oil the kukri.
Just incase if the rust does take place, dust it off using fine sand paper and re-polish or use oil instantly.
To look after the scabbard, one needs to apply boot polish to keep the leather soft. Do not let direct sunrays get to the scabbard as the leather might shrink a little making the kukri tighter to draw in and out.
Brasso or silvo (if silver case) can be used to re-polish the brass if tarnished.