Ambitious employees tend to think that working overtime is the key to success. They couldn't be more wrong.

Aspirational employees are constantly clawing their way to the top of the success tree. While there’s nothing wrong with striving to achieve your career goals and being ambitious, we often implement methods that are more detrimental to that very task than we realise.

For one, we commit ourselves to voluntarily working overtime. While we fill our heads with delusions thinking that it will get us noticed, ahead of the rest, and make us appear dedicated, committed and hardworking, the truth is that it’s just not the way to go. Think about it, if you really were an excellent employee, you’d be able to complete your tasks in the designated work hours offered to your through your employment contract and company policy. Technically, working outside work hours could mean that you’re incapable of sufficiently managing your time – the consequences of which are potentially devastating, especially if you’re in the running for a promotion.

Read: Time management and "big picture" thinking

Here are 9 more reasons why leaving on time is paramount to the advancement of your career.

Consistently staying late at the office causes stress. Your body needs proper rest to rejuvenate and re-energise for the next day - and the day after that. Healthy living cannot be stressed enough.

Successful people realise that being overworked, not having a backbone, and succumbing to the pressure of over-performing are weak characteristics.

You are too nice. It is time that you finally realise that your manager and the company are simply taking advantage of you.

Your work really isn’t that urgent and the company will not fall apart and crumble into pieces if you refuse to complete a task. They cannot fire you for refusing to take on every single extra assignment. It is your right to negotiate more reasonable expectations. If you don’t put your foot down straightaway, you will always be exploited.

Have you ever realised that the company is not paying you for those extra hours. The longer you stay at work, the less valuable you are. It’s simple maths: Calculate how much you get paid per hour, the number becomes significantly less the more hours you work.

Don’t ever sell yourself short. It’s time you realise your worth.

It is a myth that longer hours equal increased quality and productivity. If this was the case, more people would be doing it. Rather, by leaving work on time, you force yourself to be more disciplined and focussed so that you may reach your targets by clockout time. You’ll be a lot more productive if you have a personal deadline that needs to be met in fewer hours.

Read: 7 productivity habits of highly successful people

You are not judged by what you should be doing. You are judged by what you have been producing. So, if you have been producing a lot more than you should, you will always be expected to do that much, it will become the norm. The moment you do less than what you usually do, it will appear as if you’re slacking. Your extra effort, like staying late, will be perceived as normal and required, rather than special and appreciated.

The one day you do leave work not a minute later than 5, your manager will judge you negatively for under-performing.

It is not uncommon for your manager to set unrealistic goals. Now, they may or may not be aware that they’re expecting you to perform miracles, but because there’s a success hungry worker trapped inside of you, you put in extra effort after hours to conquer the unrealistic workload. This allows your manager to keep piling huge and always urgent tasks on your desks, as you’ve proven more than capable.

While you’re at the office trying to complete tasks, your personal relationships are neglected. It is wise to remember that your manager is not the one who will comfort you when you’re lonely - your friends and family are. Not only that, but you’ll change managers (and your loyalties towards them) very often in your career, likely never to see or deal with them again. However, your loved ones will always be part of your life. Choose wisely.

You are not doing anything wrong by leaving work on time. Your hours are stipulated in your contract, and you are entitled to a life outside of work. There is really nothing to feel guilty about.

If you’re too busy, you have less time for introspection to find out what you want to do with your life. Remember, you’re in effect doing someone else’s work so that they can reach their goals. You don’t need to adjust yourself, your lifestyle, and your passions, to suit your current company’s. Get out of the office and take some time to find out what you really want in life.

Go home.

Read: Enjoying your holiday is good for your career

So, if you’re the office night owl, keep these in mind to leave the office on time:

1. You are an exceptional employee, and you have a bright future ahead of you.

2. You’ll need to put your foot down and let your boss know what’s realistically possible and what’s not.

3. Before you go to work, decide on a time you’re leaving by making after work plans such as meeting a friend at the gym or going to the theatre.

4. Start your day by identifying any tasks that might prevent you from going home on time and then speak with a manager about expectations.

5. You can start small by forcing yourself to leave on time at least once a week.

6. Say no.

7. Incorporate these 13 productivity hacks into your daily repertoire.

There are more effective ways to become an irreplaceable employee. Finding a healthy work-life balance is important for your overall well-being. If all else fails, browse Careers24 jobs to find a job that will bring the contentment you seek.