As an example take this great question and answer by Dr. Steven Murdoch. It's without doubt true for its time, but it now appears to be obsolete. It says,
At the moment, it is not advisable to browse two different websites at the same time when you don't want your activity to be linked. The Tor client can't tell which tab/window you are using for each request so might send requests for both sites over the same circuit. The exit node operator could then spot the correspondence.
But this has been fixed in current versions, where different sites correspond to different circuits in the Tor Browser.
Another example is this answer by Philipp Winter, which mentions that,
You can determine the IP address of your current exit relay by, e.g., visiting check.torproject.org (you might have to be quick to catch it before Tor rotates the circuit).
This has also changed now and this method wouldn't work.
How to deal in this case with such situations in which the answer becomes obsolete?