Quarters Storage Question

I had coins in Whitman Folders for decades without coins being affected. I just changed over to albums, mostly Dansco, with a few Whitman albums. I think it depends partly on where they are stored.

I agree, it comes down to "storage", and the type of environment that you have them in.
High humidity, air exposure, gasses, temperature, etc.., etc., will definitely harm your coins given enough time.
Folders do not offer maximum protection, but even albums can fail if the environment isn't suitable.
There is no "time-frame" of keeping them in the folders.....that just depends on your specific conditions.
Newer folders can work just fine for YEARS with no signs of toning whatsoever.....I have more than a few folders myself containing "circulated quality" coins. Many are BU *(brillian uncirculated)* too....and there are no issues yet for me.

Albums "are" worth the money for you to spend though...... They'll allow you to see BOTH sides of your coins which, in turn, will allow the maximum enjoyment of your collection. which is also very important.

So, really, I'd say if you were/are going to put "Proof", "Silver Proof", high MS grades, or just expensive higher end coins into your collection...... then I WOULDN'T USE A FOLDER.
Otherwise, it may be just fine for quite some time, using your Whitman folder.

And I might say one more thing....
You could do BOTH !
Keep doing your ATB's in the folder throughout the entire series (11 years +), but then, in the near future, purchase your album, and start filling that too !
And you can buy an album that will provide the holes for the Proof and Silver Proof ATB's (as well as the business strikes).
Then you buy your annual Proof, Silver Proof, and Mint Sets to "crack open" for this album !
This is what I'll be doing ! .....

Nor just the invironment, it is also the method of placing the coins in a Folder that also has massive problems. Due to the construction of the slots, tapered, force is usually required to insert a coin into the slot unless worn excessively. I've heard of people actually using a rubber hammer to get them into those slots. Thumbs pressing on a coin too isn't really good for coins. And nothing covering coins can also present problems every time you open a Folder you risk running a finger accross a coin.