Are three coats better than two?

[dr.girlfriend]

Finally finishing up painting my dining table and chairs.  I had planned on doing three coats on the (gray) tabletop and seats of the chairs, thinking that I might need to scrub stuff off them.  Now that the second coat is on, though, and the coverage looks solid, I'm second-guessing myself.  Will a third coat be "hardier" than just the two, or will a too-thick layer of paint actually weaken the finish?  I had asked about enamel paint and the guy was a little confusing, but in the end I think I have this stuff:

ADVANCE offers the application and performance of traditional oil paint in a waterborne formula that cleans up with soap and water. It is a 100% alkyd formula water-dispersible alkyd developed with proprietary new resins that keep VOCs low even after tinting. It flows and levels like a traditional alkyd with the extended open-time required to achieve high-end finishes. ADVANCE is available in unlimited colors, giving you more ways than ever to achieve the perfect look on every job.

[peach]

Two coats is fine. Is this a kitchen table? If so, you should coat the top with some sort of sealant as just paint is not going to cut it for the high use a table top sees. I use a wipe on poly that is non yellowing and I apply many many coats with a light sand with a fine sandpaper

[Susie]

I do 3 on trim, but only because 2 doesn't cover. You can always sand a gouge and add more; you can't strip just one coat off. I'd give 2 a shot.