Is Kotor worth staying in, or is a day trip enough?
Kotor is worth more than a quick look if you can stay around the bay overnight. The old town suffers at the busiest hours, but mornings, evenings and the climb above the walls explain why people still come.
Answer
As a day trip, Kotor can feel like a set piece: old walls, a short wander, a crowded square and back on the road. Stay overnight and the bay has more range. The light changes, the day-trippers thin, and the climb above town becomes more than a sweaty obligation. That does not mean everyone needs several nights inside the old town. It does mean Kotor is better judged outside the peak daytime crush. If Montenegro is only a regional add-on, a day trip gives you the outline. If the country matters, give the bay at least one evening.