Part of the attraction of timber is the woodgrain pattern. This is a natural pattern that is similar but never identical across multiple pieces of timber. Stains and other treatments can enhance the look of natural grain.
The way a piece of wood is cut from the tree trunk will significantly affect the appearance of the grain. Wood that will be used for decorative purposes, that will have the grain on display, will be cut in a way that optimizes the grain even as it wastes some wood material. Other cheaper cuts of wood, which will be painted or covered by carpet, are cut from the tree in a more economical way because the woodgrain finish is less important.
This cuts a tree trunk from the outer rim towards the centre.
This gets a consistent and attractive grain pattern from each plank. But some wood is between the planks is wasted.
These planks will be of optimal strength or this type of timber.
This cuts a tree trunk in parallel planks from top to bottom.
This type of cut will waste very little wood, but the grain pattern will vary in shape and quality. Any plank cut through the centre of the tree will have good grain pattern.
These planks will vary a little in strength, depending if the cut was made through the centre of the tree or along the top or bottom.
You can have your timber floors re-sanded, and have them looking like new.