I used to have satellite and that was definitely an issue, but it was several years ago at this point.
It's hard to track down exactly what eats the bandwidth, but as you know, something is chewing it up.
Anything with the word 'cloud' in it. Dropbox, google drive, itunes. Basically anything that has the capability to automatically download something without your knowledge.
There used to be some software you could load on all your pc's to be able to track each pc's usage, but that doesn't really help with things like tablets, cell phones, media dongles, smart tv's, smart dvd players etc..
One thing that can be done is to look to your router and see if it tracks usage by ip address.
Typically that may not be available in your standard router, but some of the third party firmware options might allow you to track that.
Hopefully you can find the culprit.
Programmer - An organism that turns coffee into software.
If all your friends are exactly like you, What an un-interesting life it must be.
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