^ didn't use RTV or lube when I did mine, they've held up for 10k miles and 2 removals/re-installations... not a drop of coolant from them.
I'm also not terribly careful when I do engine work, mostly because I'm usually in a hurry. Just double check what you're doing when you have a few seconds in between one part and the next, and you'll (hopefully) prevent yourself from getting it all the way back together before finding a problem...or maybe prevent a potential problem from happening in the first place.