If you want to be one of those people with bad hygiene, simply do not change your toothbrush.
However, once you see the following Applied Science informational video you may get more desire to devote more attention to this accessory.
A powerful microscope can clearly show the difference between a new toothbrush and one that has been used only a few months.
New toothbrush is the one having additional fibers.
Old toothbrush is completely smooth and does not handle well when it comes to thorough brushing the teeth and maintaining thereof hygiene -- says authors of the video.