Hi everyone! We are currently scraping tar off our wood floors previously put down for linoleum. But my question for you is do we fill the cracks between the boards or leave them? They were filled in our living room and some have wiggled free in 3 yrs. these floors will be in our kitchen, mud room, & pantry. I saw leave them open and rustic. My husband wants to fill them. It's more than 2 or 3. What are the pros and cons? Under our house we have insulation.