When I buy new bras, I buy them all at once. Then I have a big stack of old bras, still wearable, but a few years old. I don’t want to give them to charity because they seem too worn (although I took excellent care of them and they’re in good condition, always washed on delicate cycle in delicates bag with delicate soap, hung dry) but I hate throwing away a wearable bra. It seems wrong somehow.
How worn is too worn?
In the case of bras, donate them unless they’re absolutely wretched and holey.
In general, if I think something is borderline, I just toss it. If it’s a little less-worn than borderline, I donate it and let the store decide whether or not to keep it.
I don’t know about bras, but when charities get clothing that is too worn, they sell it in bales to somewhere else that turns it into other things like rags or recycled stuff. There are tons of these small dumpster sized clothing donation boxes all around here. When I went on line to see who they support, turns out that they are a for-profit operations. So, apparently there is some money in recycling even the worst clothing.
Some do that…some don’t. I know a thrift store near me that throws out things that are too worn. It costs them money if you donate the really bad stuff.
My suggestion - take a sampling of the items with you to the charity, and ask them if they want it.
-D/a
Good thread. I’m in the midst of purging, and I’ve wondered this too. In some cases I just lump it all together for the donation folks to decide. But some things (old undies, holey socks, etc), I toss em outright. Some of that stuff I don’t even think the donation folks want to handle. 
Does anyone donate worn undies? I’m not sure.
Your bras sound like they’re in pretty decent condition. And bras are expensive. I’d donate em.
Clothing needs to be in at least good condition to qualify for a charitable tax deduction.
If they are too worn to donate you could repurpose them http://www.greenecoservices.com/top-20-ways-to-reuse-and-recycle-bras/
Somewhere along the line (TurboTax? Goodwill site?) the rule of thumb I picked up for deciding if something was worthy of a tax deduction was “Would you give it to a good friend?”. Depending on the charity, that seems like a good enough threshold to me. I mean, if it’s going to a place that’s going to resell it, I think it’ll work. If it’s going to a place that’s just going to hand it out to people that have nothing to wear in the middle of winter, it could probably handle being a little worse off.
Not sure where you are OP, but we have this in the UK - https://www.oxfam.org.uk/donate/shops/bra-hunt_hunt.html
Maybe do a quick google to see if there’s a local equivalent? I remember there used to be another charity who took in homeless girls and victims of domestic abuse, who specifically needed bras urgently, as long as they were wearable, they weren’t fussy.
If they’re too worn, they’ll either just throw them out or bundle and sell them for the fabric. Interesting article on Slate (it’s a book excerpt): The Afterlife of Cheap Clothes
I just took two old suits to a charity shop last week. I was worried they were too worn and they said they didn’t mind if so - they would just recycle them as other posters have said, they get a small amount for each bag of rags they fill. So I guess the key is, take the stuff to the charity of your choice and ask.
I’ve never donated underwear to charity. It might be different where you live, but I’ve never even* seen *used underwear in a thrift store.
Might be worthwhile calling a women’s shelter and asking if they have use for them. If you’re fleeing a bad situation, it might be with just the clothes on your back, and as** Bass Chick** noted, you don’t often see underwear at a thrift store.
My rule of thumb is that if I’d be ashamed to wear it because of its condition, I won’t donate it. If, instead, it’s just not in style or not as pretty or doesn’t fit as well, then I will donate it.
All good advice.
I definitely don’t feel ashamed about these bras, I just have this thing where I buy new ones every three years or so. These are in good shape, the elastic is not blown out or anything, the color of the fabric is a little dingy due to its age, but there are no holes or frays or anything like that.
I think I’ll investigate the shelter situation in my town, and if that doesn’t turn up anything useful, I’ll take them to the goodwill.