When you get your hardwood floors refinished, the daily scuffs and gray traffic lanes finally disappear. The actual sanding and coating takes about three to five days, but you need to plan for a week where you cannot walk on the wood and your house smells heavily of finish. Spring and fall are the best times to book this because you can keep windows open to air out the dust and fumes without freezing or baking.
Before you commit to a crew, get at least three quotes from local floor guys. Prices vary wildly for the exact same square footage, and the cheapest quote is not always the one you want once you factor in the quality of the poly they use. Once you have a real number, you can map out how to pay for it without panic.
That 0% window is a hard deadline, not free money. If you still have a balance left when the 18 months are up, deferred interest or standard rates will kick in on whatever is left, so treat the monthly payment like a fixed bill.