I suspected it was from a leaking roof, which was subsequently replaced before I brought the property but the wetting and drying over the years created cracks in the drywall and the vibration from the opening and closing of the garage door helped to separate the drywall from the drywall nails. 

It's these controlling provisions that you want to nail down correctly.

There is not as much to nail up." 

I would also recommend the Hometech book, but in order to have a fundamental understanding of what you're trying to do, you need to undestand exactly how much lumber, how many nails, how much drywall/tape/mud, how long it will take w/how many guys, etc etc etc.

The funny thing is that they are often very nonchalant about self management when you are looking to buy.You buy it then all of a sudden they are hard as nails about it and constantly make your life difficult.The problem is that you might not know how tough it is going to be after purchase.

Yep, Dan's post nailed it.

@Todd Dexheimer nailed it... but, I'll add some meager data.We closed on 55 units about 6 months ago. 

Nailed it!

I think other people have nailed it already. 

I DON'T spackle nail holes, EVER.