I cannot believe those two rovers are still going strong on Mars. In fact, both rovers are producing more electricity now than they were six months ago. NASA attributes this to high winds which removed the dust from the solar panels on the rovers.
In fact, the Spirit rover actually caught two whirling dust devils in action on the plains of Gusev Crater. Heck, NASA suspects a ‘cleaning event’ occurred on sol 420, when the autodrive system switched off due to poor visibility and then the power levels suddenly spiked back to levels not seen since Spirit’s arrival in January 2004. Put simply, the rover drove into a sandstorm that blew all the dirt off the solar panels and left it squeaky clean.