Instead of trading in and out of good companies, they should invest long-term and be prepared for declines, he said.
"You need to think about these kinds of challenges before you buy any stock, and most certainly before you sell any stock," Cramer said.
Cramer reviewed Nvidia , Apple , Amazon and Tesla through this lens, saying they are "four companies with riveting stories and temperamental stocks."
And investors shouldn't stick with stocks if their reasons for investing don't continue to hold up, Cramer added.
Nvidia, Amazon, Apple and Tesla did not immediately respond to a request for comment.
Persons:
CNBC's Jim Cramer, shouldn't, Cramer, it's, Tim Cook, Tesla
Organizations:
Nvidia, Apple, Tesla, Web Services