Depends on your usage patterns. Nokia 6 battery is enough for 5-6 hours of screen time, but if you play CPU consuming games or have lots of social apps/messengers syncing all the time Nokia 6 battery may not last whole day.
I usually squeeze a full day out of mine.
6am - 10pm
~3 hours of video streaming (YouTube, Netflix, etc.)
~2 hours of audio streaming (Spotify, Podcasts)
~2 hour of active web browsing
~1 hours of active talk/text
My battery is usually ~15% @ 10pm, but seems to be slighly improved after the recent upgrade from Nougat to Oreo.
I keep my app list lean. If you tend to let a bunch of junk apps run in the background, YMWV.