Because... after a few days... you'll begin thinking "I can refinish these myself". And when you wake up and think, "I can refinish these myself!", do not stupidly run out and rent a sander, hoping to refinish them yourself. Instead, take you and your ridiculous thinking back to bed. Trust me.
But say you do, really, run out and get the sander and try to refinish those floors yourself. Whatever you do, please don't plug the machine into the one outlet in the house that throws the breaker every time you start the sander motor. And when you get mad and desperate, do not unplug the refrigerator "for a few minutes to borrow the plug" and forget while those "few minutes" turn into... say... long enough to melt ice and spoil milk. Yeah.
And when you do get the darn thing working and suddenly it starts shooting sparks out of the bottom - like a welding machine on Monster Garage - it would probably behoove you not to scream like the sky is falling and run out the front door, leaving the sander churning and spinning. Just a thought. (Turns out, it does that every time it hits a nail.)
Later, when the sander makes this violent jerking motion and suddenly spews grit and chewed-up sand paper toward you with the force of a tornado, don't do as I do and shove the machine into the wall and jerk the power cord out of the wall. It doesn't like that. And a wall isn't invincible. You learn these things.
And when the vacuum thingy on the sander quits working and you don't succeed in unclogging it, don't you dare think it's okay to continue sanding. It's not. You will inhale 100+ years worth of dirt, chemicals and sawdust. Your eyes will water, your throat will seize and choke, you'll cough puffy clouds for days and your boogers will run black for weeks.
But gosh. They do look pretty great, don't they? Not bad for a girl working all by herself. As in, without anyone around while she did all the work. Not bad at all, right?
Hmm. Wonder if that sander is available again this weekend? I'll bet I could refinish the rest of these floors myself...