Stretching shouldnt be classed as an effective routine though, you need to get the heart rate elevated and get blood flowing to your muscles before hand. Not only does it get blood flowing to your muscles but it increases the delivery of oxygen and other nutrients to the muscles and gets them ready for stretching. Stretching can form part of any good warmup routine, it helps to free up joints, tendons and muscles but you really do need to get the heart moving and blood flowing in order to be effective
Ive seen a few people who have pretty good warmup routines but totally forget about cooling down, after hours of pretty full on bowling they just suddenly stop everything, thats not exactly a great way to keep things loose. You can stiffen up pretty quickly as lactic acids build up within muscles, a good cool down routine can help lessen stiffness and soreness felt the day after by giving your muscles and tendons a chance to return to their resting lengths. Stretching is great as part of cooling down, because your muscles and tendons are already warmed up it lessens the chance of an injury occuring (compared to doing the same when cold).
As long as you arent doing anything detrimental to your health, anything is better than nothing, warming up shouldnt make any difference if you are 8 or 80, everyone benefits from it. The more physical and active your game is, the more impact your joints suffer, the more you should be thinking about developing a good routine, it can help reduce your chance of suffering an injury and can lessen the effect of one if you do happen to hurt something.