As others have said, it all depends on your objective. In the Ving Tsun system I train our objective is nearly always to close, and we try to always maintain forward pressure on our opponent. Accordingly we do not withdraw our kicks. Kicks are thrust forward and then dropped to the floor without retraction. There is no withdrawing to chamber. Then we draw the rear leg up using the kick like a step to pull us forward. This helps us close on our opponent to our preferred range where we can apply punches with both hands while continuing to apply low-level leg attacks. One of our system's mottos (Kuen Kuit) is "Every kick a step, every step a kick."
One thing should be noted. In my lineage of Yip Man Ving Tsun, we keep our weight back on the rear leg so when we extend a kick and then drop it to the floor, we are not falling forward onto our front leg. We are setting the leg down in a firm, controlled movement.
Should our opponent succeed in grabbing our kick (unlikely since our kicks are usually directed at low targets) we do not lean forward onto our kicking leg to free it. We simply bend the leg at the knee (so that the lower portion of our leg angles sharply downward) and stomp our foot to the floor, freeing the leg and completing our forward step. A nice side-effect of this approach is that we often stomp or trap our opponent's front foot as we put our kick down. People unfamiliar with this approach often find this disconcerting.
Now there are those occasions when we throw multiple kicks with the lead leg ("chain kicking"). In those cases at completion, each kick is retracted a bit to set up the next one, but we do not retract deeply to a full chamber. The knee is simply flexed a bit to allow for the next thrust. Ving Tsun relies heavily on "short power" with minimum withdrawal for both hands and feet.