As the protection circuit usually has little metal strips that could potentially short out if shoddily made. I usually just crack open a laptop battery pack and know I am getting top-notch cells that have been thoroughly spec'd out and QA'd by the laptop manufacturer. Unless I add a protection board, the individual cells are unprotected, but I just make sure they stay within the green box on the voltage and temperature graph from the paper published by Stephens of Battelle, which I've posted links to before it disappeared from the web. It basically showed voltage should be kept in the 2.0V to 4.2V range and temperature should be kept in the 0 to 80degC range. Too low a voltage or temperature and the copper anode current collector dissolves. Too high a voltage and lithium plating occurs during charging. Too high a temperature and the anode solid electrode interphase (SEI) breaks down. I just avoid those extremes when running unprotected cells.