In the N-400 form there is a part where they ask trips abroad. How accurate should they be, what happens if I forget any?

The question refers to trips of more than one day made since he obtained the Permanent Residence. If they were made with Passport from there you can get very valuable information. USCIS accepts if notes such as “APROX” are posted to indicate a certain degree of security. He also accepts the note of “I don’t remember exact dates, but all trips keep the pattern of being done every year for two weeks for Christmas holidays.”