How can I fill gaps in hard wood floors?

My floors are laminate light wood. I get the best match wood filler and swipe it on scratches or holes. When it drys I use a damp cloth and wipe the access away.

I was told to mix sawdust with glue and fill in the gaps. Just make sure you match the wood than polyurethane the wood

I was told by floor repairman , for small damage to first use a wood pen to colour wood to match your wood. then use a wax crayon , they sell them for repairing wood finish. Fill the crack up by rubbing crayon over scratch / dent until level with floor , wipe off excess wax with clean cloth. I was told that this will stand up to floor cleaning better than just the coloured pen/ marker.

sI pushed dark wood filler in the space between the planks. It's lasted five years so far..the separation was was 3/8 of an inch caused from an winemaker leak