I am going to the gym 1-2 times a week for about 2 years now. I think I started to see the first signs after about half a year.I am not super well defined as I would need to go more often than 2 times a week, but you can see I am a bit more muscular than the average. However, my belly is still there, and if I am not cruel to myself it won't get away. If you want to lose weight, 90% is diet.
I recommend to shoot some photos to track your progress. When you see yourself daily in the mirror, it's much harder to tell a difference.
But yeah as others said, especially in the beginning it's much more about feeling healthy than seeing a lot of difference.
Well I blocked lemmy.ml, so no AMA for me :S