You’ve spent years swatting over your books to earn your degree of choice. And once you get that qualification, you spend many more years working tirelessly to make a name for yourself in your industry, progressing your career and building your professional reputation. But, it can take just one mistake to irreparably damage that reputation if you’re not careful and years to repair it.

We take a look at five reputation-damaging mistakes to avoid:

1. Lying

It may seem like an obvious thing to avoid making, but you’d be surprised to learn how many people make this potentially career-damaging offence.

Whether you lie about the qualifications you hold, about being sick, or ‘fibbed’ to cover up a mistake you may have made, at the end of the day, a lie is a lie and no matter how big or small, lying will have devastating consequences on your reputation.

Debbie Goodman-Bhyat, MD of Jack Hammer Executive Headhunters, says cutting corners in terms of telling lies in a job interview or misrepresenting your qualifications is a sure way to lose professional integrity and personal credibility among your bosses, colleagues and industry players at large.

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“It is quite simple – claiming qualifications or titles that you are not rightfully able to claim, can be equated to theft. You are appropriating something that is not due to you, and you are seeking personal and financial benefit from these unrightfully appropriated qualities,” she says.

“Being discovered – as you are very likely to be – will land you at a professional point of almost no return, and could take a lifetime to rectify. Play it open and honest, and build your career the tough, but sustainable way.”

2. Missing deadlines

Missing deadlines is not only unprofessional, but it’s the fastest way to lose respect among your colleagues and managers. It’s the kind of mistake that could potentially cost you a job in the future.

Beth Kuhel, a career coach and founder of Get Hired, says avoiding or missing deadlines sends the wrong impression to your employer and points to a perceived “plethora” of negative character traits.

“The main traits being a lack of motivation to excel, a lack of interest in the project and an unwillingness to prioritise the client’s needs.  On the flip side, by prioritising due dates and deadlines you demonstrate sincere interest, respect, desire to please, overall integrity and a willingness to comply with guidelines imposed by another party.

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“Being known for meeting deadlines and for producing high quality work is highly valued in the workplace particularly in today’s challenging economy where the competition is stiff,” Kuhel says.