It's fine to reuse hubs,
 

right?

I have perfectly fine Formula hubs. Though, I'm looking to get a new wheelset. As long as the rims match the hub in number of holes, I should be fine, right?

Even the bearings are fine, and whenever those give out, it's an easy fix.

Sure, unless the flanges are about to crack or something. Everything else in the hub guts should be replaceable.

Your answer ^^^^^^^^^^

I just figured maybe something happened in lacing process that made them un-reusable. I don't know.

Look at the flanges - if you're seeing cracks around the holes or any excessive keyholing or whatever, that might be a factor... but if they look solid, no worries.

Really, the number of holes in the hub doesn't have to match the # in the rims. You could lace a 24 hole rim to a 36 hole hub... I think that's right at least

As said, as long as the flanges haven't been laced so many times that the holes have deformed (which is normal) to the point where it's about to break, everything's fine.

It's probably a good idea to lace the hub up with the spokes leaving the spoke holes on the same side and in the same direction as was previously built. Spokes seat themselves into the softer aluminum hub flange so building up the wheel exactly as it was before will keep it from making new indentations.

lolz