You have a valid decision
You can make use of the 30% facility provided that you have been issued with a valid decision. The term is determined by the date on which your decision was issued.
Your decision was issued prior to 1 January 2012
The maximum term of your decision is 10 years if you applied for it within 4 months of commencement of your employment in the Netherlands.
Your decision was issued after 1 January 2012
The maximum term of your decision is 8 years. Have you previously lived or worked in the Netherlands in the past 25 years? If so, the term is less than 8 years.