Rule: Invest only for the long term /in dividends when REAL values safely, comfortably and adequately back or protect the security.
The investor in securities is like a high jumper with 3 safety blankets to break his fall. These 3 safety nets are also usually the ones that raise the security's price.
As well, the lower the price below these 3 security blankets, the better chance you are getting a good deal.
The first of the blankets that usually raise the price are dividends. Historically, people pay more for stocks that pay higher dividends than stocks that don't. On the other hand, the lower prices relative to the dividends, the better for you because the higher the yield for yor investment. Dividends will always make price drops worth it because of the higher yields.
The second blanket is the earnings figure or P/E ratio. A good earnings report usually raises the stock price.
And lastly, the third and rather defensive blanket is the equity or net tangible asset value of the company. This value is the equity, or what the owners really own; total assets minus debts or total liabilities. When the company goes into bankruptcy, these assets go into a huge garage sale or liquidation and the proceeds are the ones that the shareholders or owners get back.
Remember, the lower the price below these blankets, the better deal for you, becuase when the price falls, these are the real values that will hopefully keep you up.