While you live in the Netherlands, a passport is half an hour at the gemeente, your Dutch municipality. From Norway it is a job you plan months ahead. Not because it is complicated, but because there is one counter, you have to stand at it in person, and the appointment diary is full. The expiry date in your passport is not your deadline. Your deadline sits well before it.
Where you apply
For Dutch nationals in Norway, a passport application goes through the Netherlands embassy in Oslo. Honorary consulates in other cities normally do not take passport applications, so assume you are travelling to Oslo and check the country page at Nederland Wereldwijd, the consular service of the Ministry of Foreign Affairs.
If you happen to be in the Netherlands, you can apply as a non-resident at one of the designated border municipalities, the grensgemeenten, and at the desk at Schiphol. That is often the easier route if you are coming over at Christmas or in the summer anyway: you plan the application and the collection around two visits. Which municipalities are designated is listed at the Rijksoverheid.
In person, never by post
There is no postal application. Fingerprints and a signature are taken and your photo is checked on the spot, so you have to come yourself. That goes for children too: the child has to be there, however small. For a child you also need consent from both parents with parental authority, with copies of their ID documents.
Book the appointment the moment you start thinking about the document. Reckon on weeks of waiting for a slot, plus production time, plus collection. Collection is in principle at the counter too; whether there is an alternative varies by post and by moment, so ask when you book.
How long a document lasts
A Dutch passport is valid for ten years for adults and five years for children under eighteen. With two or three children you are effectively up every couple of years, and the documents rarely expire together. For a family that is the real planning problem, not the application itself. Current validity periods and the photo requirements are at the Rijksoverheid.
Think about entry rules outside the EU as well. Many destinations require a passport to stay valid for months after you return, so a document that expires next spring is already too short for a summer trip.
Your BSN and the RNI
Deregistering from your gemeente does not remove you from Dutch records. Your details move to the Registratie Niet-Ingezetenen, the register of non-residents, which together with the municipal registers makes up the BRP. Your burgerservicenummer stays yours and does not change.
That is more than a formality. A passport application pulls your personal data from the BRP, and if something there is wrong, the application stalls. Make sure your Norwegian address is known in the RNI and that a change of name, a marriage or a birth has been passed on. The Rijksdienst voor Identiteitsgegevens explains how to have RNI data updated. A birth or marriage in Norway usually has to be legalised before the Netherlands will take it over.
Keeping DigiD working
Without DigiD you get nowhere from abroad: not with the Belastingdienst, the Dutch tax office, not with the SVB, not with DUO. Sort out or check your DigiD before you leave, and install the app while your Dutch phone number still works. If you already live abroad and have no DigiD, there is a separate route for non-residents, and some counters in the Netherlands can activate it on the spot. The current options are at DigiD.
The nationality trap
Pay attention here, because Norway is in the EEA but not in the EU. For Dutch nationals who also hold another nationality, the law contains a ground for loss: Dutch nationality can lapse by operation of law after a long, unbroken period of living outside the Netherlands and outside the EU. That period starts again from the moment you are issued a new Dutch passport or identity card within it, or apply for a declaration confirming that you hold Dutch nationality.
Two things follow. First, renewing a passport on time is not only practical, it can also hold on to your nationality. Second, voluntarily taking Norwegian nationality can affect your Dutch nationality, with exceptions that depend on your situation. The mechanism, the periods and the exceptions are at the Rijksoverheid.
This is not legal advice, and your case depends on your family situation, your years abroad and the dates on your documents. Have it checked by the embassy or the IND before you do or fail to do anything.
Proving who you are day to day
In Norway your Dutch passport stays your identity document. The Norwegian nasjonalt ID-kort is meant for Norwegian citizens, so as a Dutch national you fall back on your passport at the bank, at the police and at the counter. Day to day, BankID does most of the work and a Norwegian driving licence covers everyday checks. But the moment you really have to prove who you are, that passport is on the table. One more reason not to let it run out.
Inside the platform this application is a recurring task per family member, with the expiry dates side by side and a reminder well before it gets tight.