Just as I do with the economy, I review the market each month for warning signs of trouble in the near future. Although valuations are now high—a noted risk factor in past bear markets—markets can stay expensive (or get much more expensive) for years and years, which doesn’t give us much to go on timing-wise.

After the good news a month ago, several of the major economic indicators I track are moving downward once again. The service sector was the biggest negative surprise, but job growth also came in below expectations. While other news was positive, particularly in the realm of consumer confidence, and there are no signs of immediate trouble, weak data for the business sector suggests the recent rebound may have been only temporary.

Last week’s economic data showed that U.S. consumers continue to earn and spend while business continues to struggle. With both income and spending up, and surprisingly high levels of confidence, consumers are still driving economic growth. Business, on the other hand, has stepped back from the stronger results of the previous several months.

As I said yesterday, the jobs numbers are (in my opinion) the most important economic data we need to watch. It seems appropriate, as the Labor Day weekend begins, to spend some time thinking about where the labor market is going.

August was a quiet but good month, as indices and the stock market were up in the U.S. and abroad. Hiring was strong, consumer confidence surprised to the upside, and consumer spending continued to grow. Still, as I discuss in this month's Market Thoughts video, the big questions concern volatility: Why is volatility so low, and is it going to continue?

Of all the economic reports out there—and there are thousands—the one I follow most closely is the employment report.

Why? Jobs are the best single indicator of what the economy is doing.

Now that summer is almost over (but not quite yet!), it’s time to start thinking about what the fall may bring.

Back in the office after my vacation, the news is generally good. Economic stats continue to surprise to the upside, markets are close to all-time highs, and the Labor Day weekend is coming. So, of course, as Eeyore, my thoughts are turning to things to worry about.

I’m not the only one either. A reader recently wrote in asking, “What about the national debt?”

With the U.S. economy trending up and the international economy improving, where should investors look? Yesterday afternoon, I was on CNBC’s Closing Bell offering thoughts on the day's market activity and the sectors to watch, including industrials and energy.

Last week’s economic news showed that business confidence and activity are still improving. Notably, the housing market continues to show significant demand, although it’s now struggling with low inventory—a problem of success. Durable goods orders also ratified the continuing growth in the manufacturing and industrial sectors.