How do people do it?

Thinking about the house renovation is getting me on my toes. I wonder how do they make the decision, of buying this particular furniture, how to match it, how to assemble it, how to move up the lift and how to make sure you dont quarrel in the midst of it all.

Lets do some calculation here:
52 weeks x 2 days = 104 days
minus 50% days which does not match = 52 days
minus 30% days taken up by work = 36.4 = 37 days

That's the number of days we have time to source for furniture, tiles and what not, and thats out of a year. I think I should start preparing now....or is it too soon? Haha!