Before 7:30pm MST, my thoughts about using primer on wood were as follows
"If I have it, I'll use it. If no, oh well!"
AFTER 7:30pm MST, my thoughts on using primer on wood are
"If I am out, I will go to Wal Mart in my pajamas and end up on this site, just to get primer."
Why the change of heart, you ask?
Yesterday, I finished one part of my 3 part window seat, and used two coats of primer before painting. The primer didn't cover well, and it didn't look pretty at all. HOWEVER.. I was able to completely cover the piece with two coats of paint. Easily.
Tonight, I tackled a smaller piece without using primer.
5 coats of paint later, I'm still trying to cover up some of the knots in wood.