Induction lamps use electro-magnetic fields to power them as opposed to the typical electrodes or filaments found in to-day's lighting.
This means there is no 'burning' inside the glass tubing. Instead, the Magnetic field excites the phosphor which in turn causes illumination.
Without the 'burning' aspect, Induction Lamps typically are rated to expire after 10-Years or ~100,000 hours. This means that if the lamps are on only dawn-to-dusk, as in a parking lot or on a roadway, they could last beyond 20-years without a relamping.
Yes, Induction Lamps will gradually lose brightness, but in 10-years only 30% of the original light output has been lost. It would be hardly noticeable.
To Clarify:
We say 10-Years.....if they are operated 24-hours/day.
However - where they are used outdoors, typically they will operate 12-hours/day.
This equates to 20-Years at 12-hours/day.
Imagine the savings - not only from having to buy replacement lamps -----what about no longer requiring periodic bucket truck rentals to facilitate re-lamping those 30-foot street lamps.
Remember too that safety procedures require a minimum of 2 crew-members for each bucket truck. What does this cost over 10-20 years?
The man-power savings alone may very well justify switching from High Pressure Sodium (HPS) or Metal Halide (MH) lighting.
AND
If Mercury Vapour lights are still being used around your Property, not only will you experience a sharp reduction in energy use - you will be able to see out there, too! (Mercury Vapour lighting lasts ~25-years.It loses 64% of it's light output in Year 1!!)
Features of Induction Lamps