When to take out voluntary insurance
You can build up AOW pension rights during the 50-year period before you reach your AOW pension age. If you only started living in the Netherlands at some time during that period, you will not have built up enough years of insurance for a complete AOW pension.
If you were not covered by the state pension insurance of another country for the years before you moved to the Netherlands, you will have ‘missing years’ of insurance. It is usually possible to buy back these missing years if you wish.