bsprague wrote:
If you take a cold dry lens into a warm, humid environment frequently, you might want one. If you live in a Florida air conditioned, dehumidified dwelling and frequently take your lenses outside without precautions, they will steam up. It goes the other way in Alaska. If you take your cold, dry lens inside from a shoot, to your hot humid dwelling, it will steam up.
I lived in Florida for 27 years and never had a problem with any of my lenses.
They lived in a camera bag in my closet.
Back in PA again, they still live in a camera bag in my closet.
No way I'm going to spring for a climate controlled cabinet.