Good Morning, 40 yards is a good range, alot of times you will get shots within that 40 yards, just sometimes you arent able to get any closer and you will need to be able to shoot farther, out here in New Mexico you will find alot of places where 40 yards in not enough. Good luck on your practice
Hope you do good with the deer, what kind of range are you practicing with your bow ? most of the guys that I hang around with shoot atleast 60 yards,, some even farther