Over the years, I've replaced most of the incandescent bulbs in my home and in my studio with LEDs. The incandescents ranged from 35 W low-voltage halogens, to 60 W standard "Edisons", to 75 W reflectors. Meanwhile, the replacement LEDs are 3–12.5 W bulbs. That's a power-requirement reduction of roughly 3,000 W for the 60+ bulbs in my studio building alone. If I were to run those lights for 10 hours/day (like a commercial studio might), I'd be saving 900 kWh of energy per month. At an average cost of $0.16 per kWh for a commercial account in Massachusetts, that would equate to an annual savings of $1,728. Just a few years ago, good LED bulbs cost $20 per bulb. The bulbs I purchased most recently were $7 per bulb. Do the math, and you'll realize that the initial investment in the bulbs will pay off very quickly in energy savings. (LED bulbs last for decades or longer; therefore, you won't be purchasing new bulbs very often.) So, which bulbs should you buy? Other than bulb shape, light output, color temperature, beam width, and wattage — all of which are usually specified in standardized metrics — you should be concerned about audible noise, EMI/RFI, flickering, and dimmability. These last four traits are associated with the driver electronics in the LED bulb, which from my experience, can make or break a bulb (so to speak).