: A primer may also help promote a good bond between the epoxy and paint.

: Nick, it's that word "may" that scares me.

If I pray real hard it "may" help me win the lottery.

They sell primer with the promise that it will improve the bond, it probably does, but many people have successfully painted their boat without primer. And the finishes have lasted well.

I guess "best practice" would include the use of a primer specifically designed for use on resin (even if it is designed for polyester, it should work with epoxy) with your paint of choice. I don't think you will notice a difference in the appearance of the finish, and the difference in the longevity of the finish will be small.

If you are going to use the boat, you are going to scratch the paint, and a little bit of primer under the paint isn't going to make look much better. At best it will keep the paint immediatly surrounding the scratch on slightly better.

Plus it may also improve your chances of winning the lottery.