If your ignition module is failing then your engine will suffer from poor performance such as engine misfire, loss of engine power, reduced fuel economy and hesitation.
If your ignition module does fail then your vehicle may suddenly just die in the middle of the road and you won't be able to start it again.
If your ignition module is failing you should get it replaced before it does fail completely and leaves you stranded on the side of the road or in a worse case should your engine suddenly die in the middle of the road cause you to get run over and killed.