Repair some bad wood or patching missing board with exiting one or to continue additional room with same or new type of floor.
Some of your existing floor could have dark stain spot that could be cause by water damage or pet stain, usually can never be sanded our. So most of the time it needs to be replaced to give it a better look.
Most of these damages are usually caused from wood floor that is covered by carpet, which usually leave nail holes and stain marks.
