How many worms are in your stackable bin?
You just might not have enough food/worms for things to happen.
In most stackable bins, with 2#s of worms, and enough food, you should have started to harvest compost for the first time in 5-6 months. After that, once again, depending on the # of worms and food provided, you might be harvesting every 2 months.

removing moldy food... but it is my understanding that the worms don't eat the food itself as much as they eat stuff eating the food. (microorganisms and such). Maybe you arent feeding them enough for the population to grow?

That was my initial thought, that I did not have enough wormms--they only gave me half a pound with the bin. But it's been more than 3 years!! Shouldn't I have alot of worms by now? That is my worry here--the level isn't rising because there aren't enough worms, right? But I thought they multiply reasonably rapidly, and I figured a year tops for the worms to increase and the level of castings too also.
The manual with the bin said something like 3 months or so is required before I use the other bin on top, with a pound or two of worms. 3 months? Okay, maybe 6 to be realistic. But my bedding and castings level has not moved an inch--in fact, as I mentioned in my earlier post, it has DECREASED. I'm beginning to think that they are either constipated, eating their own poop and bedding, or in need of worm viagra. What gives? Should I give up and just do my outdoor worms-in-a-compost-pile? But I really enjoy this bin at my workplace, everyone thinks it cool too. It is teaching us all about composting, etc.

You got any fishermen in the office that might need some bait from time to time?

1/2 lb of worms is not many worms. I don't know many of the variables about your bin, (feedstock, temperatures, moisture, etc)
Right now, (and I am guessing), I would get more worms working in your bin.

I think you are right, and it was my guess also, that I do not have enough worms. But I am still puzzled as to why I don't have at least two lbs after 3 years...They have multiplied, they seem happy, they are in a controlled office temperature environment, and they have crushed eggshells, etc., everything that I have read about. Their favorite foods are melons and I leave the food in till it's gone unless it rots to the point that maggots come in. They just do so much better outside in an outside compost situation where I don't coddle them, just throw things at them and voila--lots of worms.
I will try with more worms but it's still a mystery as to why I needed 2 lbs to begin with...worms have to start pro-creating just like all living creatures, right? I wouldn't question any of this stuff if I just started the bin 3 months or even a year ago. Oh well...

im new and learning and this is off topic but What food are you putting in that gets maggots?
I leave the food in and its usually gone pretty quick but even if its left and gets rotten i have never gotten maggots.

Flys like to lay eggs on rancid meat more than anything else.

Bedding will be reduced in volumne in time. They do eat everything in the bed over and over. Everytime they produce better and better castings. I have one bed that is 4 ft. square and 4 ft. tall. I have filled it to the 3 ft. level at least a doz times. Every time it gets to 2 ft. I add another ft. of bedding. I don't know how many times I threw a 5 gal. bucket of shreaded newspapers in it also. Your worms may have adjusted to the amount of bedding that you have and are just not multiplying. Mabye more bedding might help. They do kind of self regulate themselves sometimes. One other thing, do you have a lot of people checking them out at the office. (They may need so privacy) Just a thought.

"I leave the food in till it's gone unless it rots to the point that maggots come in."
I would guess those larvae are Black Soldier Fly, not housefly. That is another sign of too much food, too little worms

something to think about is that anything that you are doing that might affect the microherd of bacteria will also have an effect on the worm population. Like misting with chlorinated water or something. Probably not your problem but mabye someone elses.

Thanks for all the advice. Just to clear myself up, I don't mean that I always put in too much food till I see maggots--I meant that the two times I have seen maggots, I removed them and the food immediately.I was trying to make a point that I never leave in too much food, and that maggots tell me it is too much. It happened when I put in a watermelon rind that was way too big.
It is a relief to know that they do eat their bedding over and over. That explains a lot. I did add more bedding last month. I will add even more now, and get more worms too.

My company is small, and no one looks at the worms unless I check on the worms myself(then they will come over to watch). I know this for a fact cuz the bin is located behind my desk and I sit there all day. So they do get privacy.
I am looking forward to vamping up my bin's population now that I know what the problem is. Thanks again!

The saftest way to makw sure that you don't feed to much is to let them eat all of the last food before putting more in. As long as you have plenty of bedding they will be fine during the time between feedings. The biggest problem with the bins is not having enough worms to handle the food load that is being put in. Then comes the moisture problems.