There have been some important things said. Also a poor shaving technique is also very hard on the edge, there is a sweet spot with the angle of the shave that gets the most life from the edge, because it cuts so efficiently, which also leads to a better shave. It could also be that your technique was spot on the first time, but not so much the second time. There is a strong argument for lightly stropping after each shave, also how many effective laps before each shave.