@davidjamesweir @nemobis I have usually tried not to get any extra attention from the tax office, but when I have failed, they have been very nice. Once I forgot to pay, and some two months later they contacted me about My Tax Situation. Nothing urgent, just to let me know that I still have tax to pay, and the interest at that time had accumulated to some 0.50€ – less than the cost of sending the letter by Posti, probably.