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

What: Shares of specialty retailer Tilly's (NYSE:TLYS) fell 10% today after the company reported earnings.

So what: Revenue at stores open at least a year fell 0.9%, which is a terrible sign for any retailer. Net income fell 29%, to $9.8 million, or $0.32 per share on an adjusted basis, better than the $0.30 per share analysts expected. Guidance is what really had investors worried. The company expects earnings per share in 2013 to be $0.75 to $0.81, when analysts had expected $0.95.

Now what: As usual, in earnings season, it's all about guidance. Net income guidance may have fallen short, but the company does expect to grow in the low single digits this year, which is a change from last year. There are better retailers with more competitive advantage, so I think Tilly's is still too expensive to jump into right now.

Interested in more info on Tilly's? Add it to your watchlist by clicking here.

Fool contributor Travis Hoium has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.