Window Caulking

The edges of every window should be sealed with caulking to prevent energy losses and water damage. But after time the seal will become brittle and crack.

Use a utility or putty knife to remove the old caulk. Be sure the area is clean and dry. Then apply the new caulking in a steady stream (avoid stopping). Smooth over the caulk with a putty knife or a finger and examine the seal for any thin layers. Add more caulking to thin spots and gaps. If the caulk is applied too thin it will crack when dried. 

Notice the gap in the center and the crack to the right.