Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The Dow Jones Industrial Average (DJINDICES:^DJI), trading higher for most of the day, fell suddenly in the last hour of trading Monday, shedding more than 100 points to end below session highs. U.S. Secretary of State John Kerry had harsh words for the Syrian regime, which, U.S. leaders say, used chemical weapons against its own civilians last week. Escalating rhetoric surrounding the attack is sparking fears that the U.S. may intervene, a move that could further stress the relationship between the U.S. and Russia, which supports Syria's Assad-led government. The Dow ended with a 64-point, or 0.4%, loss, closing at 14,946. 

Home Depot (NYSE:HD) tacked on 2.1% today, adding to gains that have made the home-improvement retailer a great investment in 2013. While Home Depot stock has surged 22% already this year, patient, long-term investors who believed in a housing recovery years ago have more than doubled their money, illustrating once again why the buy-and-hold philosophy is far from dead. Home Depot has grown its earnings at a remarkable 18.4% compounded rate over the past four fiscal years. 

Aerospace mainstay Boeing (NYSE:BA) tacked on about 0.1% Monday and was one of only four blue-chip stocks to end in the black. While talk of military intervention in Syria may have given Boeing's stock a floor today, what's more important to investors is guaranteed business: China's Xiamen Airlines completed an order for six 787s today, which should bring in about $1.3 billion in revenue.

Microsoft (NASDAQ:MSFT) stock lost 1.7% today, in its first full day of trading after CEO Steve Ballmer announced his impending exit. Today's lackluster performance is a stark reversal of fortune following Friday's 7.3% gain. Monday's fall is most likely a reflection of some short-term profit-taking, although it's possible that long-term shareholders who want Ballmer to remain at the helm of the software giant -- should such stakeholders exist -- took some chips off the table. 

Lastly, Procter & Gamble (NYSE:PG) lost 1.8% today, ending as the worst performer in the Dow. Investors looking for a takeaway from the day's slide should look elsewhere; no serious developments were holding the stock back, with P&G's decline coming on a day with lower-than-average volume. The consumer-goods behemoth, while hard to mistake for a growth company, instead offers investors a respectable 3% annual dividend at current levels.

Fool contributor John Divine has no position in any stocks mentioned. You can follow him on Twitter, @divinebizkid, and on Motley Fool CAPS, @TMFDivine.

The Motley Fool recommends Home Depot and Procter & Gamble and owns shares of Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.