So after the discussion in response to my question, I've started training a little lighter and using more sets.
Previously I was doing 8-12 reps one set. If I did 12 reps, next workout I added 5%. Each time I trained to complete failure. Generally 5% was small enough that if I did 12 reps at n, I could make at least 8 or 9 at n*1.05.
Now I'm doing 3 sets of 10 for each exercise, 1 warmup at around 60-70% of workout weight, and two at workout weight. And I'm not intentionally taking these sets to all out failure.
My question is when to move up weight? So far, I've just moved up if the 10 reps for each set felt a bit too easy. Is there a better way to decide? I'd like to make strength gains as fast as is reasonable and safe, since I'm still pretty underpowered (I weigh a flabby 250, and for reference am benching 115 for workout at the moment, just started sqautting and DL and I'm only doing 115 there as well, though my lower body is strong and I should do better on those once I learn the form).
I've now been training for about 3 months 2-3 days a week.
Second question is whether there's a good exercise for tendonitis besides wrist curls. I've started doing those regularly and using a restrictor and I'e pretty much eliminated the tendinitis in my forearm (from racquetball), but now I'm noticing some tendinitis in the back of the elbow at the base of my upper arm. I'm not sure where to put a restrictor for that or what muscle to strengthen. I do triceps extensions and close dips pretty much every workout. Anything else good for that?
A part of deciding when to move up is instictive and invloves knowing yourself. It will get easier with experience.
In your situation I would just keep moving up in 5%-10% increments. When you find yourself getting too close to failure keep the weight the same for the next workout. Here is what a sample log might look like:
115 no problem
120 no problem
125 no prblem
130 too close to failure
130 no problem
Your previous indicator for increasing weight was "no failure after 12 reps". Your new indicator is "Not too close to failure after 10th rep of last set" What is "too close to failure"? This is where the instinctive part comes in.