One would be enticed to sell or buy many times.
Thats where mental preparation comes handy.
Easiest is to just leave it all alone.
Best is to Buy.
Mentally, be prepared to buy. It will be hard. Its not easy to buy even $JNJ at $80 and then see it drop to $49.
It takes some discipline. It takes some practice.
To be always be in a buyer's mindset.