fabric doesn't prevent weeds it prevents the roots from burrowing into the dirt. If a weed does happen to start, a simple tug and it comes completely out
What about nutsedge and other weeds that grow right through the weed fabric? Then you go to pull it and the fabric comes up? Or what about if the area isn't completely flat or the water runs down through the low spots or channels. Bye bye mulch. Try newspaper to suppress the majority of the weeds first. THEN DO REGULAR MAINTENANCE. Contrary to popular belief THERE IS NO MAINTENANCE FREE LANDSCAPES. Unless maybe a plastic landscape? Nope you'd have to sweep it.
I often figure in an extra time to come back and spray at least once for non regulars.