Halogen lights would need maintaining almost every 2000 hours. That means in commercial places like retail you would need to replace the lights every 5 months. Replacing a halogen track light including the labour would usually cost around $80
Metal halide on the other hand if good quality bulbs were used, would last from 2-3 years. The problem with these lights was the control gear would also need high maintenance after a few years and the bulbs themselves were expensive. Replacing a track light that is metal halide including the labour will cost over $120 each time.
Running cost commercial lighting:
Metal halide and halogen running cost are very high, most commercial set ups would spend over $10,000 a year running 60 fittings and around 3 – $4000 in maintenance costs.