Being skeptical of everything is no wiser than believing everything.

Reflexive doubt and reflexive acceptance are the same failure with different manners. Both replace the work of evaluating a particular claim with a general policy, and both feel like a stance rather than a shortcut. The person who disbelieves everything is not being careful; they have simply chosen a default that never has to be revisited.

Judge claims one at a time. Ask what the evidence is here, for this, and let the answer differ from case to case. If your response to new information is always the same regardless of content, you are not assessing anything, whichever direction it runs.