The face ages due to multiple conditions including gravity which pulls the fat pads of the face downward, the thinning of these fat pads and the insulation fat layer of the skin itself, and the damage from the sun resulting in loss of elasticity. This results in a turn from a triangular face with widest part at the cheeks/temples to a square type face with heavy lower third of the face due to jowls and loose skin. This can be addressed with fillers such as Sculptra or Radiesse for the cheeks and Belotero for the lips and undereye regions to lift up this loose skin and fill it back up reshaping the face back to its youthful triangular form.
You can see in this image how the filler is evenly spread all the way from the nasolabial folds to the temples in order to create a smooth voluminous appearance.
For those who are also bothered by skin laxity of the neck, the neck skin can be tightened surgically in a facelift or non-surgically using laser energy in a laser facelift or Lazerlift.