The waves are crashing over the side in the markets as the Dow dropped more than 800 points today (3.15%), the NASDAQ dropped more than 4%, and the S&P lost 3.29% today!

Market sell-offs can unnerve even the most strong-willed investors. These kinds of drops can feel incredibly painful, but it's useful to remind yourself that this a natural part of the markets.

Just like everything in life - this too shall pass. I find it helpful to remember my time horizon. As a long-term investor, I'm looking out 20-25 years. Just as there are sell-offs, there will also be many boom times, too.

Remember that you're never going to buy at the absolute bottom or sell at the absolute top. As always, work on your shopping list, pick your buying levels, and do your homework.

Don’t buy all at once.

By buying in stages, sell-offs can feel more like picking up your favorite stocks on sale instead of feeling like your profits are slipping away.

Have any particularly exciting (or gut-wrenching) stories from your portfolio over the past five days? Feel free to commiserate with me in the comments!