What is the best way to determine what cricket bat size to use? This is a general question but my specific case is for my 8 year old son.
Good question. A common mistake is to select a bat that is too big for a young player. The temptation may be to buy a large bat for the player to "grow into", to save money as much as anything else, but it's definitely not a good idea. The bat should feel comfortable to and manoeuvrable by the player.
Bob Woolmer's Art and Science of Cricket has this to say on choosing a bat for a young player (p.101):
Personally, I would err on the side of caution and opt for a bat that is lighter rather than heavier. The last thing one wants is a bat that impedes the development of good technique.