As of yesterday, my portfolio currently totaled $5,797.42 for a growth of $689.99 since the conception of the portfolio. At this time, none of the assets that I own are trading for a negative value of what I initially loaded into them for. Although there are some that are close to being an asset that does not trade in the positive numbers (KSS), the great majority of the portfolio at this time gives nothing to be concerned about immediately. This doesn't mean that this can't change. It's important to keep an eye at least weekly on the status of your portfolio because there may be a company that once was only riding the line of being worth your time when suddenly it could find itself plummeting into the depts of the penny stocks. The trick is to catch those stocks before they reach the bottom.
If a company that I own suddenly takes a turn for the worst and starts falling like a rock, my first idea is to check where I currently stand with the stock. If it appears after quick research (because time is money in this case) that the downturn is a trend that is not likely to bottom out and come back up, I do in fact think about selling. This isn't to say that I don't ride downturns at times (GE had a downturn when I first loaded in). It is simply to say that we need to see what caused the downturn and see if they would be able to recover from it. There is no point in staying in a stock simply to be long on something when their share price can't keep up with the market. The idea is to not only make money from your dividend payments but also to make money from capital gains when you are able to.
Capital gains are important for any portfolio, dividend growth investing or not. If you are not making capital gains on your investments, you're either not investing as clean as you should, or you simply had a stroke of bad luck as can sometimes happen with a stock and trying to time them. If my portfolio suddenly turns for the worst with everything I'm invested in, I should quickly discover with research that it is affecting the market as a whole, not simply the stocks I invested in. This is because the only things I invest in should already be companies that can weather a downturn. With this being said, we need to make sure again to keep our eyes on our portfolios because there are always exceptions to every rule.