The Tor Project web site makes a bold claim to its users:
"Tor Browser prevents someone watching your connection from knowing what websites you visit. All anyone monitoring your browsing habits can see is that you're using Tor."
Don't misinterpret this claim. It's not true that Tor protects you against "anyone monitoring your browsing".
On this web page, I provide you with the critical information missing from the Tor Project's website: if you estimate your adversary's resources in dollars, I'll estimated the probability that Tor will fail to protect you.