And then if you own property where you currently live... and you're planning on doing one of those buying/selling things where the proceeds from your old house directly go to the down payment on your new house without ever hitting your bank account first...
It's like what if I put my house on the market too late and it doesn't sell before I move? What if I put it on the market today and it sells tomorrow, and I haven't even given notice at my job yet and neither has my spouse and the person wants to move in next week?! What if I sell early and everything goes fine, and I've bought a new place where I think I'm going... and then I get off a waitlist at a school I'd rather go to three hours after I get the keys to my new place, hundreds of miles away from that school?
All the uncertainties. I'm feeling you.