When I started my company Greenback in 2009, I had the very romantic notion of loose HR policies: unlimited vacation, very few meetings, and flexible reporting arrangements.

So I never would have imagined that instituting such a lenient vacation policy--which would allow employees some much-deserved freedom--would backfire. I've since managed to fix it, and hold true to the general ethos of keeping the team light on "rules," but it wasn't easy.

Here's what went wrong, and how we've improved our unlimited vacation policies to include more clarity and guidelines.

People took off less time, which led to more burn out.

This was the most baffling trend my company experienced when the team moved to an unlimited vacation policy: less time off. In the absence of guidelines or benchmarks regarding what was acceptable, I found that the team started taking less time off in an effort to show commitment.

Everyone was so careful about not wanting to take advantage of the policy that they went the opposite direction: They were cautious about days off, and some started to experience job burnout and stress.

What was the solution? My company still has a "use what you need" vacation policy, but has also implemented a minimum vacation policy. Managers encourage their teams on a quarterly basis to book a week off, thereby setting the tone that this is welcomed, and the minimum vacation policy includes the rule that each person must take off at least five days in a row.

It didn't work for new hires.

The philosophy around "take what you need" vacation time is based on trust: Get what you need to get done as part of your role, acknowledging that this includes building in rest and time to think.

However, to be honest, that doesn't really apply for people new to the business. When a new team member starts, what they need first is time to learn, absorb, and get up to speed.

Plus, when a team member first joins Greenback, my team is carefully assessing whether what they believe they saw in the interview process matches with the candidate in practice. They're still in a quasi-trial mode.

After having a few new starters immediately take weeks off when they join, Greenback implemented a policy whereby a team member needs to be working for three months before taking holiday time. It also has set the right tone. I believe in work hard-play hard, but my team can't really "play hard" if they haven't also complemented that with the right contributions to the business.

Employees needed a little balance.

I highly encourage "use what you need" or "unlimited" vacation policies. Not only is it a perk, it makes for good business--employees who take time off to rest and recharge are better when they're at work too.

However, it is important to also make sure that you have a few guidelines when setting your policy, so that it works in practice as you imagined it in theory. As with so many other things, finding the balance is the key!