Hmm both of mine were really young when we started off leash and are dependable 98% of the time, lol.
In dog training I learned you can keep a 6 ft leash on them and let it drag on the ground. This way if they take off you can step on the leash or grab it. Stay away from dogs that are acting crazy and their owners aren't paying attention, this is a recipe for disaster when you're unsure of your own dogs recall.
It's a lot easier to do off leash if you've mastered leash walking first.