People give very different answers to this and I think the range is real: somewhere between 3 months and 2 years depending on severity and what you're able to do about your situation.
I had what I'd call a serious but not catastrophic case. About 18 months at a startup where scope kept expanding, feedback was basically nonexistent, and the culture was 'we're a family' in the way that means 'you'll sacrifice for us.' I left in late 2024 with nothing lined up.
Weeks 1-4: I mostly slept and ate badly. Didn't feel recovered, felt like I was catching up on a deficit that had been compounding for a year. Productivity guilt was constant. Felt like I should be applying to things but when I sat down to do it I just stared at the screen.
Months 2-3: Actual interests started coming back. Started doing side projects in ML again, not for any career reason, just because I was curious again. That curiosity returning felt like a marker. I was probably around 60-70% of baseline.
Month 4: Started interviewing. Made some errors in early screens that I attribute to still being in recovery mode. Specifically, I was too transparent about why I left in a way that some companies read as a red flag. Calibrated that over time.
Month 6: Accepted a role. Felt genuinely excited about it, not just relieved.
Month 8 in the new role: Would say I'm close to full baseline now. The cynicism mostly burned off. I notice I care about the work again in a way I hadn't for a long time.
A few things that seemed to actually matter: physical stuff (sleep schedule, moving my body every day even briefly), genuinely logging off rather than continuing low-level stress monitoring, and being patient with the timeline instead of fighting it.
The one thing I'd tell someone early in recovery: the first few weeks feel the worst because the adrenaline or whatever that was sustaining you finally crashes. It gets better after that crash. That part surprised me.