He suggested that in the future I put my new lenses on a shelf and point them towards a window. The light would prevent the mold from growing.
I'm going to address this seperately from the above, just to keep it simple.
I wouldn't keep lenses "facing a window" especially if direct sunlight ever came in through that window. At several points inside a modern optical system, such as a zoom lens, the light is concentrated into something called a "circle of least confusion", you're probably familiar with the effect if not the name. Ever burn a leaf with a magnifying glass? As you moved the glass back & forth the image expanded, contracted & distorted to that one "sweet spot" wher the light's concentration ignited the leaf. That spot is a circle of least confusion & you can see the effects of long term exposure to direct sunlight!
Older (film) cameras frequently had obstructions, iris mechanisms, reflex mirrors & shutters inside that tended to block the effects. Unfortunately many modern digital cameras dont, all the light stops at full intensity at the CCD where the lens is focussed, again a hot spot just waiting to scorch.
In use cameras are usually mobile so the effect moves about before any serious damage is done, but there may wel be a warning about NOT storing the camera facing "bright lights" without the cover attached, this is why.
How to store well?
Simple few rules & you're GTG.
Dark is fine, but moisture is to be reduced, or eliminated with dryers, or ventillation.
If the lens just came in from oputside on a cold day it will
form condensation of moisture, both inside & out. You can't wipe it away from the insides, just the outside, so wiping isnt a 100% answer. Just leave it out in the open till it equalizes for temperature & it will evaporate naturally causing no problems, after that put it back in its case or bag.
If it gets rained on do the same thing after wiping off all you can get at from the outside.
If the bag, or case gets wet empty it, open all the access you can & let it dry before putting any equipment back inside it.
Scopes, binoculars & so on can use the same techniques to keep them healthy for decades.