96 Geo Timing belt TDC Question

Hi Everyone:)

I am replacing the timing belt on my 96 metro 4 cyl. for preventitive maintenance. I am curious why I need to worry about TDC.
I plan to just take the old belt off and slide a new one on without moving anything. Is that a bad way of doing it. Is it mandatory to get TDC?

Thanks,
Greystoke

you have to align the marks on the cam gear and on the crank gear to make sure its lined up right, it moght turn 1 tooth when you take old belt off or put new one on

Thanks for the input. I will be sure to use TDC.