It really depends on your comfort level at your place of work and that's as basic as it gets. The irony here is that you just can't afford to feel comfortable in any place of work for the simple reason that these places aren't designed for comfort. You have to operate like a special forces soldier in enemy territory, alert and alive to the slightest movement in your immediate vicinity or beyond.
As they say in the special forces, you sleep with one eye open and your boots on and you will have to find your comfort level in these conditions. Now, don't get disappointed by this depiction of the workplace because it's another manifestation of the market where you're competing with scores of others - the more the competition, the murkier the conditions.
If you're absolutely comfortable in such situations and also have the talent and skills to handle your job with confidence in such conditions, you're the unstoppable rockstar who will go places. Not all people are able to remain in one company for too long and those who do, normally have less turbulent careers.
One common indication that it's time to leave a company is when the workflow in your direction starts decreasing till it becomes a trickle or stops completely while your departmental colleagues are loaded with work. The other is when you have either not been appraised or have not received any raise post appraisal.
There could be other more instantaneous reasons for an altercation with your HOD or an immediate senior following which you find yourself being gradually isolated. People, however, leave their companies for different reasons that are not related to any compulsion whatsoever.
Some leave soon after appraisal when they get a raise and join a new company with a 50% higher package. They would negotiate the new package soon after the appraisal and join the new company with at least three months salary slips of the new package. This is normal for most folks at the beginning of their careers.