Over the last 4 months I have had trouble.

Over the last 4 months I have had trouble starting our 2004 Sequoia. We bought it used in 2009 and within 3 months had to have the starter replaced. Now when I try starting it, I will here just a click. I turn the key all the way to off and try again and it will start up right away with no problem. But I may have to do this multiple times before it will start. Other times it will start the first time right away. We to it to a local mechanic and the battery tested good and of course the problem never presented itself over 150-200 starts while there. I just can't imagine that good starters would go bad after only 4 or 5 years. Kind of expensive to keep replacing starters at $1000 a time.