How old are you, bud? Have you been working out for a while, or are you just starting? If you have been working out for a while, you probably will not notice any measurable size on your arms in just a few months. It might take me a year of heavy lifting just to add a half inch to mine. Now if you are new to weight lifting, your first few months should spur an impressive looking growth spurt. Actually, I’ve heard that it isn’t really growth, but rather all that fatty tissue inside your muscles being squeezed out to the outside of your arms where it is more noticable. I’m not sure about that. It sounds rather hokey to me, but that would explain why so many new people in the gym notice such quick growth in their first couple of months. If you are working out hard, eating right, and getting plenty of sleep, a half inch of growth a year isn’t bad. Say if your arms right now measured 14 inches in diameter. If you workout hard, in about 5 years they’d be up to 16.5 inches, and in another 5 years they’d be at 19 inches. That would definitely impress everyone you know! Hope this helps. Don’t get discouraged, though. Bodybuilding is a lifestyle change, not just something someone would do for 6 weeks or so. Good luck!