The best duration to choose is the duration which best fits with your personal goals and circumstances. Start with when you want to retire, and also consider your worst-case retirement date, just in case, and pick a pension plan duration that fits with your life plan.
In relation to the pension plan options themselves, the 15-year and 20-year options have a clear advantage over the 10-year option – they both offer minimum guaranteed profits (of +40% and +60%, respectively) in addition to the 100% capital guarantee, whereas the 10-year option has “only” the capital guarantee which means that you won’t lose any money in the worst-case scenario of a particularly big stock market crash just before your target retirement date.
Before deciding on a duration, have a look at the various articles on www.PensionsForNomads.com which are there to give you the knowledge and information you need to fully optimise your financial planning as a digital nomad, and use it to think about, research, and create your own financial plan which will make sure you turn your dreams into a reality. Then come back to thinking about which duration to choose – you might find that by then, you already know which one is best for you :-)