Originally posted by: KoolDrew
You switch to an intermediate program when you can no longer make progress on a beginner program, not when your strength reaches some random number.
Agreed. I would recommend checking out Rippetoe's book
Practical Programming. It is a follow-up to
Starting Strength and explains the distinction between a novice, intermediate, advanced, and elite lifter. It has nothing to do with how much weight you are lifting; it relates to whether or not you can progress using the routines suggested for each level.
Another way of viewing it is to think in terms of work loads and recovery ability. A novice requires fairly easy workloads relative to their true genetic potential to disrupt their body's homeostasis enough to cause a growth response. Because these workouts are rather light relative to the novice's genetic potential, they can recover from them quite quickly. This is why linear progression is used on a daily basis in the novice routine.
Eventually, the novice will reach a point where they are no longer able to progress from one workout to the next. In a sense, the amount of weight they must now use to disrupt their body's homeostasis and produce a response exceeds their ability to recover from it when they are using this load 3 times per week. They must therefore insert less stressful workouts in between the high intensity ones in order to give their bodies adequate time to recover.
Advanced and elite lifters require even longer periods of lighter work to recover from high intensity work because they are lifting weights that are so close to their genetic potential.
This is a very brief summary of the ideas presented in the book. I found it to be a very good read and I would recommend it to anyone.