Hardwood floors are low maintenance but certainly not zero maintenance, like any surface that is part of your home cleaning they will of course need regular cleaning to get up dirt and spills and every now and again they may need more extensive maintenance.
A hardwood floor that comes with a finish on it or has been waxed is especially easy to clean and wipe with a cloth or mop or sweep. The finish stops dirt getting ingrained but the surface itself needs looking after and is in many ways more fragile than the wood it protects.
If a hardwood floor comes with a finish don’t add wax or other treatments to it, until the original finish really is past it. Also be careful what cleaners you use, they should be non abrasive and if possible PH neutral or slightly acidic, in which case it is important to wipe residue away afterwards.
The best thing however for hardwood floor cleaning is to sweep regularly wipe with a simple wet cloth or mop as soon as any spills have been made. This way dirt won’t have a chance to get walked in which can not only stick and make a floor look dirty but damage the surface through scratching away the finish.
With varnished wood the varnish itself will eventually wear down but is easy to reapply so you shouldn’t need to worry too much; wax is better at protecting the wood from moisture but can be slightly more tacky and mean dirt sticks and the wax itself starts to look dirty.
You could of course simply leave your wood bare or stained, yes wood can get damaged and wooden floors are expensive but if you have proper wooden floors, and not veneers, then any damage can be got rid of by sanding or stripping down the boards.
With harder woods especially though the wood shouldn’t get damaged easily and will age with time in such a way that it will develop character, especially with a wood like oak that will also age through darkening.
If your hardwood floor does need cleaning more thoroughly to remove trodden in dirt and stains then use a specific hardwood floor cleaner, these are formulated to leave your floor looking not just clean but add to the luster while some floor products, especially those containing ammonia, may dull wooden floors.
The main thing that can cause serious damage to wooden floors is water, the effect on plain hardwood floors is more that water can stain, water has more of an effect though on soft wood such as pine and on stained and varnished floors where these can be damaged themselves. Do make sure that if you use water to clean a floor dry it up and it is better to use a damp cloth rather than more water; if you do spill water accidentally then do clean it up.
Hardwood floors should make your home cleaning easier overall but it is easy to ignore them, remember that if you do ignore the needs of your wooden floors you may have more work long term.