I started recall training with my two the day they came home (if they never do anything else well I do want a recall). First inside the house, then in the (fenced) backyard and only then did we leave the yard. When we are outside off lead I will call them back often (and reward them). My rule is (and it's probably the rule I'm most consistent with because it's most important to me) that I call them once. If they don't come back immediately it is now a leash walk. I don't get angry, just call them once - go collect them (Max actually) if they don't come and snap the leash on. They never get off leash anywhere near traffic. Max has developed an obsession with squirrels so we don't even attempt off leash if there are likely to be any in the area. I'm not comfortable having a dog leashed in an off leash dog park so I wouldn't go there if I felt they needed to be on leash but I am 100% confident in both of their recalls away from other dogs.
I can only speak from my own experience but it wasn't until about 5 months old that Max even considered not coming when he was called - until then both of my dogs thought the sun rose and set on me. Rylie does have excellent recall except when I'm trying to call him away from hubby (he is a daddy's boy). He loves his people far more than any wildlife.
Mindy Tri - Feb/97
Max - Ruby - Sep/08
Rylie - B&T - June/09