Don't get fazed by historical market catchphrases like "sell in May and go away" or data showing September is typically the worst month of the year for the stock market. 

Yes, the S&P 500 has clocked a 0.5% average decline during September since 1950, according to data from LPL Research.

But stocks traditionally post declines in August as well, but this year, the S&P 500 clocked a 3% gain during the month.

"When we look at some of these seasonality patterns - we've got Lehman Brothers included in that [data]," said Brian Levitt, senior investment strategist at OppenheimerFunds and panelist on TheStreet's Trading Strategies roundtable. "What we always want to be focused on is more of the macro picture and less about what these seasonal patterns are."

Levitt reminds investors that $100,000 invested into the market right before the 2008 collapse of Lehman Brothers was worth $50,000 by the end of that year - but is worth $255,000 today.

"I don't think we should be so focused on monthly patterns," he said.

Watch the full Trading Strategies replay here