The doctors will tell you it is bad to wear the contacts longer than the prescribed period.
Someone may think it is because they want to sell you more contacts. But actually, there will be a very thin layer of calcium over the contact surface when it is used over time, which will prevent enough oxygen from getting in. Blood vessels would probably grow over which will cause inflammation and make it easy for infection, even possibility of blindness. We only have two eyes, what we can do it to take care of it, and avoid any risk or possibility of damaging it.
It is right for you to clean it before your wear it every day. The step of cleaning is so important for the wearing of the contact lenses. But it is not right to wear contact lenses longer then directed. Usually one should wear the contact lenses less than 8 hours a day. Or else, the eyes may feel dry because of the air proof in the eyes. If you keep on doing this, the eyes may get infected. Thus, you'd better not do this.
You'd better not wear contacts too long, because contacts will affect your eyes when they are going to produce more water. Generally speaking, you cannot wear them more than 10 hours each day, because your eyes need time to rest and revitalize. So, you should reduce the time you use them each day. prescription glasses are good alternative.