Only you can decide if the posts will last another ??? years
The problem with rails is timber shrinks away from the nails, so I prefer 25x25 hot dip gal box tube with battens screwed with gal or zinc screws hex head for easy fixing.
Last one I did was 1991
I still own that home and the fence is still there good as the day it was done.
A neighbour here had a fence done in hardwood about 10 years ago and I have been refixing battens for the last 4 years.