Sanding before staining traditional wood floors?

These boards look as tho' they already have a coating on them? If so, there's a good chance that fresh 'stain' will not go on well.

Ideally you should sand the floors first and this gives you an ideal surface to apply stain to.

This is where it gets tricky - I cannot recommend the best stain/dye for timber floorboards as I simply don't know what it is.

This has been a bone of contention for me for decades as I've often sanded and coloured floorboards in my houses. Sometimes it's worked out well, and other times it's been disappointing. The problem is, when it went well I'd never remember what I used when I moved house...

It all depends on what shade of finish you are after. If it's quite dark, then you may be ok simply coating the existing boards with a coloured varnish.

If, however, you want to emphasise the grain and keep it light or mid-shade, then I suspect you'll get better results from first apply a stain/dye, and then clear-coating over it. But stain/dye will really need freshly sanded timber first.

I hope others on here have had good success here and can recommend solutions. 'Cos I'd love to know too...

 

First, are the boards completely unfinished? Have they been sanded before?
If unfinished then yes they wod need sanding as bare solid wood would have plenty of irregularities. If finished with anything then the stain won't hold on. So in both cases sanding should happen - the collected dust should be mixed next with proper gap filler (keep in mind that if the boards have too much moving space meaning your subfloor does not provide enough support then the gap filler would eventually fall down in places) then you should decide on type of stain - light, dark and etc. but again some stains are used with oil and some with lacquer so you need to be aware how are you going to seal the floor before choosing the stain.
For example woca have some really good stains but they are used only with oil - read more on woca here if you like https://www.flooringsuppliescentre....finishes/creative-floor-finishes-by-woca.html
Other stains can be used with both like Morrels and Bona but they usually say it's best if you finish with lacquer.
Anyway when you apply the stain after sanding and gapfilling then the whole floor would be one colour including the gaps.
If you stain without sanding and the wood is unfinished then you would probably regret it as the result might look as patched work and the you still need to finish it.