Depends entirely on how complicated your income/expenditure is. This year was the first time in 10 years or more that I needed to add to my pre-filled tax notice (major reno, deductions worth it). I may have missed out on a few hundred € of deductions in that time, but my simple life has always been listed immediately correct: Income from work done in the country, benefits, voluntary retirement insurance, stocks&funds wins, losses, dividends. Finland.
Depends entirely on how complicated your income/expenditure is. This year was the first time in 10 years or more that I needed to add to my pre-filled tax notice (major reno, deductions worth it). I may have missed out on a few hundred € of deductions in that time, but my simple life has always been listed immediately correct: Income from work done in the country, benefits, voluntary retirement insurance, stocks&funds wins, losses, dividends. Finland.