Holding on during rough times represents a true test for the long-term investor. However, due diligence is always recommended. A company or industry might not pull through. Ultimately it is your decision on whether or not to keep shares in a company.
Once upon a time if you wanted to get a risk free return on your investment, you put cash in a savings account. If you wanted a superior return, you risked at least part of your cash in the stock, bond, and/or commodities market for a shot at superior returns.
Now, in this low to negative interest rate environment, you get almost no risk free return or even have to PAY to keep your savings safe. Increasingly, you need to risk at least part of your cash just for the potential of a return at all.
Record low interest rates translate into stock bubbles as investors seek a decent return on their investment. This means that some companies will trade at excessive valuations even though fundamentals may be stagnant or eroding. Do your research before investing and make sure that valuations aren’t too excessive. Also, it may pay to keep some cash on hand to invest during any potential corrections.