Floor finishes and certain chemicals in wood oxidize and are affected by ultra violet light sources. This may cause the wood and finish to change color and develop a patina or aged appearance. To avoid uneven appearance, move area rugs occasionally and drape or shade large windows.
If your wood gluing work is less than successful, check your blades. If the blade in your saw is getting dull, it can loosen (but not remove) a layer of fibers on the edges to be joined. Later, glue may not be able to penetrate through this debris to solid wood, resulting in weak joints. A signal that this may be the problem is if ruptured joints are coated with fibers.