How often can you sand a wood floor?

It really depends on the condition of your floor and the type of wood. Generally, you can sand a wooden floor multiple times - some floors can handle 3-5 times, others even more. The limiting factor is the layer of solid wood you can still sand without hitting the plywood or the support structure underneath. With solid planks or parquet boards that are several centimeters thick, there's considerably more room to work with than with thin engineered parquet. It also matters how deeply you need to sand each time - if you only have to sand the surface because of scratches or unevenness, your "reserve" lasts longer.

There should be several years between individual sanding sessions. It doesn't make much sense to sand constantly - if the floor still looks halfway decent, leave it alone. Only sand it when there are new scratches, significant wear, or when it's really become unsightly. With normal use and good maintenance, you'll go longer between treatments anyway.

If you're unsure whether your floor is still in good shape for another sanding, a look from below can help - check out the basement or look through a window into the adjacent room from above to see how thick your floor structure really is. Then you'll get a better feel for how many more times it can be done.

That's not quite as simple as just giving you a number - it really depends on how thick your finish is and how deep you need to sand! Generally, you can sand a wooden floor maybe 3-4 times in its lifetime before the wood gets too thin, but some floors can handle more than that.