I still agree that it causes ambiguity about how much time off is "too much".

If you're a startup, that can be painful to cough up.

Fast forward to 6 months into the job and I've taken days off for long wedding weekends and have some more extended travel planned in the future.

I agree that "unlimited vacation days" can be a red flag, but it really just means to be more curious and thoughtful about the culture during the interview process and find out what it really means.

Now, some of my coworkers are workaholics and won't take that much. But I have had success in just saying "I want to take these weeks off."

I work for a company with unlimited vacation, and in my first 10 months working there will have taken ~3-3.5 weeks of vacation days cumulatively that I probably wouldn't have if I had to conserve a limited set of days. Nobody has given me crap over it, nor have I felt pressured to not take those days. It's just a matter of having a company that actually wants reasonable work-life balance for their employees.

I think that our relationship with vacation has to change to one where we consider it a vital part of being a professional. When that attitude shifted for me, I became a pretty big fan of the unlimited vacation policy.

I figure that the worst case scenario, I'll get denied the vacation and I can choose if I want to move on or stay..no harm done.

So - if you are a high performing individual, you can make it work for you, but for a lot of people, unlimited days morphs into no days.

But - I think your kicker really captures the impact of this policy "t's just a matter of having a company that actually wants reasonable work-life balance for their employees."

I'm heavily paraphrasing Kahneman here, but numerous experiments have shown this effect in a variety of ways. Perhaps most counterintuitively, in an experiment where an arbitrary limit was set on the purchase of soup on sale, the amount of soup people bought was twice what was bought when no arbitrary limit was set. I'm not aware of any empirical studies examining this with vacation days, but anecdotal evidence like this seems to support the influence of this effect. I'd be extremely interested to see the data on the number of vacation days taken by employees at the no set vacation companies vs. others.

It really depends on who you're working for.

Even better, in a few places you don't have to be let go encash leaves.

My last company had a leave encashment policy. I remember, I hadn't taken a single leave in 5 years. I knew many of my senior colleagues hadn't taken one in 7+ years. When the mandatory leave encashment period arrived, we ended up with a quite a good chunk of cash.

After that the leave encashment policy was amended by the then CFO, realizing what had just happened. The new policy was designed to have a concept of 'leave expiry'(If you don't rest, may be you don't deserve rest in the future).

I guess the new CFO's now realize, 'leave expiry' policies force the other kind of culture- where every one wants to take leaves which now forces the people who other wise don't take leave to take it, because no one wants to 'waste' leaves.

So the most obvious solution is to put in a 'unlimited vacation'. So that the onus of leave is on you and your manager, if you there is ever a free time in your project you can have that vacation(Which will never come to pass anyway). This way you neither have to pay leave encashment nor have employees who enjoy full benefit of leaves. Instead the company as a whole now has lesser employees taking fewer leaves.

I'm certain the productivity and quality of live of many if not most people will decline over time without sufficient time to relax and focus on non work related things. Especially in high-tech/creative/innovative field I never understood how this is not understood by some people /companies.

No set vacation means no vacation quite often. Institutional ideology works on unwritten rules. So officially yeah leave any time that's cool, un-officially if you leave and Joe Smith here is working nights then well guess who'll get a talking to be about lack of motivation and performance.

I think the best policy is generous vacation time (4-5 weeks) and being forced to take it. The whole saving for a mini-retirement is problematic. Also I have noticed most people don't recognize burnout. So that forced time to rest and do something else is more beneficial than it appears on the surface.

EDIT: To add. I am becoming more convinced that vacation policy is one of the best proxies that show how much companies care about their employees' well being and happiness. Now, don't get me wrong, I am not saying companies should do that. It is up to them. They all will say the do though, but that is one metric that shows if they really do or not.

It depends on the nature of the employment. A few occupations (notably in banking) have MANDATORY days off. (Forcing bankers in certain categories of jobs to take vacations is a good way to detect long-term embezzlement schemes.) But there are definitely programming jobs in the United States in which the company says, "You can take time off whenever you like," which in practice means "You can take time off whenever the company isn't in crunch time," which ends up meaning never. Freedom of contract and flexibility in working arrangements is the hallmark of the United States economy and indeed is one of the reasons that the United States is as wealthy as it is--people choose the trade-offs they like among many possibilities.

Also, to save you a few years of surprises, here are some other factoids:

there's minimal healthcare, likely to be canceled by the next president

minimum wage is the equivalent of 5.33 euros and for waiters its only 1.57euros

Payday is not mid month but well after you do the work.

You can be fired at anytime without any waring for any reason from most jobs. Frequently a security guard will escort you out of the building.

But on the upside:

There's a death penalty in 3/5 of the country

The notion that the world is 6000 years old is sometimes taught in school.

You can buy a gun instantly in most states.

We have a per capita GDP almost as high as a northern European country.

We may not be socialist. Well, ok, some people say we are so never mind.

That's not vacation in my book. When I leave for vacation I don't touch anything related to work. With vacation time, I just request it and as long as there are no conflicts the time is mine to use. I have no responsibility other than not being at work. I worry I'll lose that disconnect with 'unlimited vacation.'

I work for a startup with unlimited vacation and know several others that do as well. Anyone who wants to take a vacation can take it at almost any time and for weeks at a time - no questions asked. The only time I've ever seen any conflict is when there was a major release planned at the same time as the beginning of one vacation, in which case the employee just pushed it back a few days.