How soon after starting a new job did you realize you needed to leave and find something else?

At one job, I knew the first day. I never stopped my job search. It took me almost a year to find another position but I wasn't wrong about my first instinct.

I knew in the first three hours, but stayed 6 months. I went to work for a management group and they assigned three clients to me. Normally you manage one or two, but I was told I had so much experience that it would be fine. The position was fully remote but they required to know every single minute I was working. In addition to working all day, I also had meetings conducted by Zoom in the evenings two or three times a week. It was a salaried position. I was very overworked and asked my supervisor for advice to catch up, she told me that this was great timing because the next week was Thanksgiving and the holiday would give me two extra days to catch up. I didn’t work on the holiday. I quit the following February.