Some windows have UV protection on them (and it can be added) to minimize damage from direct light. Some lights have UV from them that can also damage fabric.
Now, My Stash is in a room that is rarely used. There's black-out liners on the windows and the lights are kept off.
How much time is the room used with light that your stash is in?
Doors on cabinets also help keep out dust. I like my shelves open so I see at a glance what's in there. There are 6 6'tall bookcases 30" wide filled with fabric. Some I've had for 20+yrs and don't notice any light damage.
Just some rambling thoughts.
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