Space b/w floor boards

What is an acceptable gap between old baltic pine floor boards. Some of the boards have shrunk over the years and I am now thinking of polishing them. Only problem is that some of the gaps between the boards are over 5mm (some boards have shrunk from 150mm to 145mm). Should I pull them up and replace or just leave as is These gaps are wider than in the rest of the house.

(also some of the nails have rusted severely and damaged/rotted surrounding wood. Any thoughts/ solutions/ fixes to stop further problems)

Thanks

Hi Prof,

5mm is big, see my post Finishing a restored 60yo timber floor, I pulled up anything bigger than 2mm, but my cypress flooring had more than big gaps, there were chunks missing that had been bogged up, and more. It's really up to you but it could be ok if your happy to have the gaps and damaged nail areas as a feature. Alternately you could leave the floor down and repair the cracks and damage, or you could pull up and relay as I did. Both are really time consuming. Hope this helps.

Nick