So, I started going to the gym about a month ago. Doing dumbell curls I started at 10lbs. I tried 50lbs at first.
Mistake!
Sized down until I got to 10lbs. I was looking for the first one I could do 20 reps. Then, as days went on, I kept moving up sizes. I'm currently at 25lbs. I keep wanting to move up to 30lbs, but my body gives way around the 12-15 rep range. So, not quite there yet. But the first 10 reps of 25lbs aren't even hard anymore. It only gets increasingly more difficult after the 10 mark, but more often than not the 15 mark. 15-20 are the hard ones.
But with 30lbs it's hard right from the start.
So, should I be doing the 30lbs reps, even if its less than 20 reps? Or do the 25lbs reps which I can easily do 3/4ths of before it becomes a struggle for the last few reps?
It depends on your goals, but for muscle growth 20 reps is a little high. 8-10 is a good range and then you can progress up to 12 reps before increasing the weight again.
Ex: week 1 30 lbs 8 reps
Week 2 30 lbs 10 reps
Week 3 30 lbs 12 reps
Week 4 35 lbs 8 reps
Etc
My goals are strength training and weight loss. I'm just kind of going to the gym, kicking my own ass for 3-4 hours a day, and then doing it again.
Just starting out, but I've already felt some improvement, and lost about 4-7lbs depending on the day. It fluctuates.
If you want to get leaner and stronger, you should focus on bigger movements and not single muscle concentrated exercises. Pull ups, rows, bench press, deadlifts and squats. After whole body lifts, you can focus on single muscles like biceps. If you do them while fatigued by other lifts, you have to tune the load accordingly.
Most important of all: look at your form and stick to the movement. Let the weights down before going out of form. Weight is the tool, not the target (in your case!)