Short answers, pulled from the story.
The Mars Exploration Rover mission lasted sixteen years. Spirit was active until the 22nd of March 2010, and Opportunity until the 10th of June 2018. NASA officially declared the mission over on the 13th of February 2019.
Opportunity traveled more than 45 km on the Martian surface, far exceeding its designed goal of 600 meters. On the 23rd of March 2015 it crossed the marathon distance of 42.2 km, and it previously surpassed both the Apollo 17 Lunar Roving Vehicle and the Soviet Lunokhod 2 rover for total distance driven on another world.
The rovers were named by Sofi Collis, a nine-year-old third-grade Russian-American student from Arizona, through a NASA student essay competition. Her winning essay drew on her experience growing up in an orphanage and her hope that America would let her dreams come true.
Both rovers found strong evidence that liquid water once existed on Mars. Opportunity found Jarosite, an evaporite mineral that forms when salty water dries up, along with layered sedimentary bedrock and hematite-rich spherical concretions formed in an aqueous environment. Spirit found goethite in the Columbia Hills, a mineral that forms only in the presence of water, and later confirmed carbonate-rich rocks at an outcrop called Comanche.
Spirit became permanently stuck in soft Martian sand in a region near Gusev crater. NASA announced in January 2010 that it would be used as a stationary research platform. The last successful communication with Spirit was on the 22nd of March 2010, and NASA ceased attempts to contact the rover on the 22nd of May 2011.
The initial 90-sol primary mission cost 820 million US dollars to build, launch, land, and operate. The first four mission extensions added 104 million dollars, and the fifth extension, granted in October 2007, cost at least 20 million dollars.