You switch around machines serveral days a week? I use three of my machines on a regular basis, but I don't have more than five and four of them are fitted with the new bulb. The old bulb in my 99 still works fine, and I'm in no hurry to replace it. I use a bit of extra light too, the best I found is a reading lamp with a 40W halogen bulb. I can adjust the light to wich ever angle needed in additon to the embedded light in the machine. It feels very close to optimal. The LED bulbs are getting better but so far the best light comes from my halogen reading lamp.