The answer to 'how to maintain hardwood floor' is to regularly clean and protect the surface. This includes sweeping, vacuuming, and mopping the floors with a wood-safe cleaner. You should also periodically apply a hardwood floor polish or sealant to protect the finish from wear and tear. It's important to avoid using too much water, which can damage the wood over time.
Proper maintenance will help keep your hardwood floors looking their best and extend their lifespan. If you notice significant scratches, discoloration, or other damage, it may be time to have the floors professionally refinished.