For short term it is 3 days for one location& for long term it is 7-15 days.
Many people prefer 7 days , a week is a good amount of time to enjoy and experience the North East. Accounting for two to three days of travel and transfers, that leaves four to five days for excursions and activities. If you’ve got more than a week, consider splitting your time in different areas of the North east rather than spending it all in one place.
For week end Trip, it just Two days