question for weight lifters

I used to do crossfit and I noticed major changes within 4-6 weeks.

A physical change took a bit longer, but seeing the weight on my lifts increase every week is all I've ever needed...

3-4 weeks was when my wife noticed an overal increase in firmness

I saw small changes in 3-4 weeks

I noticed a change in 2 weeks, but that was just BF% loss not a muscle gain.

ETA - It obviously depends on your program and consistency. I only lift for 30 min, without much of a rest. There is always something going on. In between bench presses this morning I had to do one legged squats, repeat.

When I started lifting I was eating on a slight deficit and lifting consistently 3 days per week. I noticed I was getting smaller in my torso and arms especially, but could feel the muscles (couldn't see them yet) after about 3 - 4 weeks. It took my lower body a little longer at about 5-6 weeks to see a change.

Without knowing exactly what you are doing it's hard for anyone to say. When you say "how long before you noticed a change" what are you specifically asking? If you are trying to lose fat, weight lifting alone is not going to cause it to happen. Weight lifting while in a deficit is only going to maintain the muscle you have. But if it is a well designed routine, as a beginner, you will "possibly" see some gains as long as you try to progressively lift heavier weight at least every week. Don't listen to what most people will tell you that lifting the same light weight from week to week is going to magically cause you to tone up. It doesn't work that way. Good luck and maybe this helps.

Now let the flaming begin......................

Soooooo If I'm eating at a deficit (1200 cals avg) and begin the strong lifts program (with still abt 20lbs to lose before GW), I won't gain muscle? So will the ones I already have (I swear they're there, I can feel them sometimes! beneath the layer... if I flex...) still develop more or would eating at a deficit be detrimental?

Muscle growth requires a few different things. First muscle can't be built from nothing, so first it requires a calorie surplus. It also requires protein, there again it can't be built out of nothing. And last it requires a sufficient signal to tell it that it needs to grow which is why you lift weights. Also if you lift the same weight with no consistent increase in poundage/volume, then it has no reason to grow any bigger. If it can already lift say 25 pounds for 3 sets of 10 then why would it get bigger if it never has a reason to?

Now after saying all of that beginners using a well designed routine can, for a short time, build muscle while losing fat. So to answer your first question, yes, you can potentially gain "some muscle while in a deficit if every other requirement is met. To answer your second question lifting weights is the most important thing you can do to hang on to as much muscle as possible while in a deficit.

The reason most people think they are building muscle while they are losing fat is because they are just uncovering the muscle that is already there, but you don't want to lose any of that muscle while you're losing fat or you're going to have to build it all over again.

I've been at it almost 5 months, and I'm just starting to notice the bigger changes in my body. However, I am still significantly away from GW, which I'm sure slows down the noticeable progress. But, I have massively increased my strength gains. My squat went from 45 to 165, my deadlift from 45 to 175, my bench is at 65 and my OHP is at 55 (just started both these lifts, but have already had strength gains). So, to me, that is HUGE progress in only 5 months. The body will come with time and a deficit.