Anyone know paint?

[SeattleVet]

8. Definitely better to use a separate primer.

Some paints are called 'self-priming', that actually contain no primer, and I don't see how they can be anywhere as effective as a separate primer coat. The primer will help the paint coat adhere, and, if you use Kilz or something similar it will help to control mold problems.

Depending on the color you are using for the finish coat(s), you can use a light (white) or dark (usually grey) primer so you don't have to apply as much of the topcoats.

Here's some good background info on the use of primers and what 'self-priming' paint is actually good for:

https://www.thespruce.com/self-priming-paint-real-or-scam-1822383