[eldod]

Very true, bandwidth is very expensive today. Some comments to your post:

- Actually, and quite surprisingly, the "cache everything" mode only adds around 25% of used bandwidth in practice. But even 25% is already a big difference if you pay 10 or 50K of CDN bills per month.

- Indeed useless bytes download can create overall congestion brings harm to the network in general, and should be avoided. It's especially true for websites that don't have the money to pay big CDNs and stream with dedicated server with limited capacity.