Then I started to use 3 weeks as I started having kids and they were getting older.

Now, I work for myself and usually take about 8 weeks a year for various things. I always work when I am off, just not as long (like 2-3 hours a day). I have to admit, I don't think I could go back to only 1.5 weeks of vacation. The flexibility is also what will keep me working for myself rather than going back to run someone else's company.

To the point below about the top employees enjoying the unlimited vacation...this is true. The whole policy is designed for companies that give trust to their employees. Sure there are challenging times for employees to use vacation, but I'd rather grant an employee 8 weeks of vacation one year due to personal challenges or those rare cool vacations than put a cap on vacation time and risk losing great employees. At the same time, I also want to know the employees that abuse he policy because in my experience, they are usually the employees that have other concerns and need to go anyway. And yes abusing the policy can be even taking 3 weeks off for the year when basically everyday in the office tends to be a vacation day when you look into it more closely.