My "warmup" is usually one set of 135 for like 8, not really doing anything. I am aware that is probably not enough, but I have never warmed up in my life. I probably should start doing that.
Now I was being a smartarse in my post above, but honestly if I didn't warm up I'd tear every muscle I'm working LOL.
I've seen guys come in cold, load a bar with a buncha weight and start going.....never in my life have I been able to do that.
If I'm gonna work chest I'll start on a flat machine and do about 5-6 sets with increasing weight for 20-30 reps a set. Even then I'll start chest with something like Hammer Inclines and load four plates and rep 35-40, 6 plates and rep 25-30, 8 plates and rep 20 and then 10 plates and get about 10. After that I'll still start with sets where I'm still getting 20 reps before I get into rep counts of 4-6. I gotta be fully warm before I get heavy.