Particularly for bright prime lenses, I always use neutral density filters.
In general, primes either limited or A star labelled would over expose the photos by at least 1.7 stops in bright light. The images tend to be clipped as well.
Neutral density filters tend to preserve a lot of rich colour without too much areas being clipped.
Neutral density filters also worked very well for water fall photos where 1 sec shutter time is preferred with aperture around 16. (If you want the silky beautiful water flows)
Then graduated filters helped in conditions like sea landscape at sunset where the colour of the dramatic sky is difficult to be metered and the foreground colour are preferred to be preserved.
I had seen MsKad's amazing Creek photo in a forest where graduated filter did the trick!
Another example of using graduated filter to preserve the colour ...
I also used the filter to get more details on people's faces in street candids.
P.S. The neutral density has +, 2+ or 3+ that usually indicate how much more darker with crecendo numbers