A very different kind of countdown is coming to the businessworld in 2020.

That's when the 80 million millennials (ages 18-31)are estimated to make up 50% of the employee population.

Whether this milestone is celebrated or not will dependon how well your organization is prepared for this demographicchange. I recommend businesses create strategies in advance ofthis historic shift to make sure they are prepared for theopportunities and challenges to come.

Here are five things for companies to consider in 2015 so thatthey are more than ready for the big millennial countdown:

1. Hireleaders

The Hartford's 2014 Millennial LeadershipSurvey found 83% of millennials consider themselves to bea leader today and 73% aspire to be leaders in the nextfive years. The workplace is the No. 1 area where they want tolead, with most of their current leadership in their personallives.

Consider that personal leadership as a great trainingground for professional leadership. If you arehiring employees in 2015, I suggest you look for Gen Y candidateswith leadership experience outside of work, including in communityorganizations, school groups and sports teams.

2. Offer training

While they feel like leaders now, millennials recognize thatthey need training and development to be effective leaders in theworkplace. Consider making 2015 the year that you create aleadership succession plan – or refine your existing plan – andoffer the training and development necessary to put the plan inaction. If you can't offer in-house training, provide millennialswith ideas (and ideally funding) for external training resources,such as online classes, local college courses, books and blogs.

3. Creatementors

A reverse mentoring program, in which new and experiencedemployees mentor one another, is another way that you can help yourGen Y employees become the next generation of leaders. Reversementoring allows a company to benefit from the expertise of eachgeneration, such as knowledge transfer from long-time boomeremployees and the tech skills of digital native millennials.Reverse mentoring can also provide engagement and networkingopportunities to those who may feel ignored, such as Gen X'ers whoare stuck in the middle of two massively influentialgenerations.

4. Becomeflexible

When asked about what an employer could offer to retain youngemployees, millennials in The Hartford's poll said flexible workschedule (58%); merit-based salary increase every six months (41%);and insurance benefits (38%). Don't we all want those? You willmost likely attract and retain employees from all generations ifyou strive to offer a good work-life balance, fair-market salaries,and benefits that help protect employees' health and wealth.

5.Protect your leaders

Don't forget to protect your employees. Now that you've targetedyour future leadership, be sure to offer income protection andcommunicate the value of this benefit. Employees who havedisability insurance return to work after an illness or injuryfaster than those who do not have the coverage. That fasterrecovery can help your company with its productivity and can helpemployees with their personal and professional goals.

The millennial countdown to 2020 is coming. With some planning,you can be ready for it – and even celebrate it.