Just because someone is approaching retirement doesn't mean that their productivity will wane and you should look to replace them with fresh blood.

In fact, retaining older employees can be more beneficial to businesses. After all, the 50+ age group is predicted to represent one third of the working population by 2020.

Read: Age discrimination is widespread in the job market

Here are five benefits to embracing and valuing your older employees.

1. A cost-effective workforce

Bringing in new, younger employees on lower salaries might seem a better move financially than retaining older, well-paid staff, but is it really?

First you have to think of the cost of a new hire, which is always a lot more than their salary. According to a report by the Society for Human Resource Management, cost per hire can go as high as $5,582 in some industries–on top of an employee's salary.

Then there's the fact that older, more experienced employees require less training than newer employees. They're more aware of industry best practice and existing technology.

Plus, employees closer to retirement age often don't require expensive benefit plans such as company health insurance.

2. A more flexible workforce

When you lock a new employee into a contract, it's almost always one with a set amount of hours throughout a standard working week.

This can be limiting to employers who could do with extra support at certain times; younger workers may have family or commitments that can't be changed.

You'll find that older employees are more able to change their working patterns, giving you greater flexibility in your work-hour scheduling. Older employees often prefer to work part-time rather than full-time, too, adding even more benefit.

3. Greater experience and responsibility

When push comes to shove, it's comforting to know that you have an experienced workforce in place that can handle it. Older workers give you this security.

A lifetime of experience compared with just a year or two is incomparable. The ability to adapt under pressure is something that older workers have experienced countless times throughout their careers.

4. Role-model leadership

It's that experience and responsibility which make older workers so valuable – particularly in how they can impact younger employees.

A report by the Society for Human Resource Management revealed that older workers are more open to sharing work ideas with colleagues and more willing to speak up when problems arise.

There's a lot that younger employees can learn from older ones, saving you money on future training.

5. Commitment to the task

All of the above features–being cost-effective, flexible, experienced, and helpful to others–result in older workers being more committed.

Their years in employment give them a greater understanding of how to adhere to company guidelines, and the importance of punctuality in the workplace.

Older workers are also found to be more engaged, which ultimately boosts revenue, according to SHRM.

The study found that 65 per cent of workers age 55 and up are considered "engaged" in their work, compared to 58 to 60 per cent of younger workers are.

Despite the benefits of retaining older workers, businesses don't always pull their weight. Find out why HR is out of step with the over 50s.