3 months noticable
6 months significant
I'm at 1.5 years now but have had a few months off... and I'm happy with the way I look. "Built" but not big by any powerlifting/bodybuilding standard.
3 years if training is perfect to a 'male model' physique (bench 1.5 bodyweight and other similar lifts, with 10-15% bodyfat). As I said I'm not there yet ..... Not really aiming for it either but thats just what I noticed from people I've seen.