I have fairly new natural maple 3/4" [about 4" wide] flooring installed. The installer was sloppy and where the flooring butted against doorways (no doors, just open frames), he should have side cut the vertical door moldings and placed the planks under, but he just straight cut and I have gaps. In the worst case I have an L shaped hole, 3/4" deep, 1/2" wide and about 3"x3".
As a result food from the adjacent kitchen, and water and anything can get in these spaces. I've though of filling with white silicon caulk to match the white moldings, or maybe beige to try and match the floor. But I'm thinking that 3/4" deep is too much for that.
I have matching planks, so I could cut possible cut a couple of 1/2" pieces for the big gaps, but that won't work for the narrow gaps. I'm skilled in woodworking.