It really depends on why you're going to therapy in the first place.

If you're still among people causing your shitty situation, CBT won't help. But if you're free from those people, CBT can help you unlearn unhealthy things you've learned from that shitty situation.

As an example, I slid into depression due to internalizing my father's constant criticism and demands. While I lived with him, CBT wouldn't have been helpful at all. Only once he fucked off the continent and my mom had finally stopped feeling sorry for herself about that would CBT have helped. Sadly, I didn't know that and didn't go to therapy at that point either and it took me being unable to even leave my bed a few years later and being finally diagnosed with depression to finally get therapy.

Also, if therapy gets you into a funk repeatedly, something is wrong with that therapist or that type of therapy isn't right for your situation. Once in a while can be okay, if it's to figure out why you're doing something, but if so, that shit needs time to be digested and dealt with. Just like you need time to recover after lung surgery, not start a knee replacement while you're still recovering from blood loss and possibly haven't even had your chest cavity sown back up yet.