I use them at home for mailing bills and things I bought the large box because I didn't want to purchase the small box and then come back in a month to purchase them again. However the large is is too large. It's hard to find a place to store that many envelopes in a small home office. I think there should be a medium sized option.
Used for all mailings business and personal used to organize receipts order forms invoices customer name tags anything and everything that will fit and the #10 business envelope will hold a lot.