Just get into your basement and see the window. If you see a lot of dust in your windows or weeds growing out of your window in the window wells then it is time to search for good quality windows wells. If the window wells are not proper in your house chances are there that leaves, grass, and even water might enter the window wells and make it ugly when you see from the inside of your basement. The design of the window wells have to be good so that it prevents water, grass, leaves from depositing inside the window wells. Apart from that if you had chosen a good model basement window wells then proper lighting would also enter the basement.
There are times when you see water leak from the windows in the basement. This happens when there is water stagnant outside the window. If there is no proper draining system installed along with the window wells then this might happen. A draining path along the outer wall or inside the wall that starts from the based of the window near the window wells is a must. This drainage pipe can be lead to the drain sump. If you find that your windows are leaky in the basement then it is time to install such a drain system. Good quality basement window wells will not have this problem of leakage in the basement.