All of the above options will cost you, either in terms of money or pain and suffering. The costs of replacement are fairly obvious--up to $12,000 for an average-sized house--but even sanding will cost you in terms of labor and clean up.
A good, thorough cleaning of your wood floor may do the trick instead. Because water is the enemy of wood flooring, wood floors tend to get broom-cleaned and damp mopped more than properly cleaned.
One important thing to note about wood floor cleaners is that the vast majority of them are vegetable oil-based. This means that they are biodegradable and non-toxic, an important factor if you have toddlers.
This is not the case with every wood floor cleaner, and we will point out the exceptions to this rule.