From what I gather, the ISP has to record the sites you visit—but not the specific pages. Does VPN stop my ISP from seeing the loaded sites? Or do I need Tor for that? I’m not too concerned about complete privacy, I just don’t want every website I just don’t want my browsing history to be leaked.
It neatly circumvents this bullshit, some suspect doing so will put you on a list for a closer look but if your traffic is innocuous who cares, I'm more worried about my useless ISP leaking/losing such data than I am about state intelligence.
Just the existence of these databases held by ISP's built under lowest cost bids will make them a massive target.
Also if you are visiting https site your ISP only see domain name, not pages.
I only ask, because routing everything over a VPN provides the illusion of privacy while flipping contracts every month provides some element of real privacy. It is easy enough to check on the activity of people pretending to hide their activity (assuming GCHQ has access to the same access that the NSA do), but real resources have to be spent tracking down people who actually hide their activity.
I have no idea how they allocate their budget for tracking potential threats, but somebody flipping prepaid sims would warrant a closer look if I was analysing the logs.