After its graduation in 2003, he attended Kozyn Driving School. Then, Serhii did the military service in the town of Yavoriv, Lviv Oblast.
From January 30, 2013, to August 30, 2014, he actively participated in the Revolution of Dignity. He took part in the Hrushevskyi Street Riots and defended the Ukrainian House. Serhii was severely shell-shocked on Maidan. Because of the serious problems with his back, he felt pain when walking. Despite all this, on August 30, 2014, Serhii started to fight in the war. Since that time and till his death, he fought in Aidar. At first, he was a volunteer there, but in February 2015, Serhii signed a contract until the end of the special period or, in other words, till the end of the so-called Anti-terrorist Operation.
Firstly, Serhii Kochetov was on a reconnaissance mission, and then, he became a senior gunner of the mortar platoon in Aidar 24th Assault Battalion of the 10th Mountain Assault Brigade.
The night on November 1 became fatal for him as there was a combat. As a result of mortar shelling near the village of Slavne, Mariinsk Raion, Donetsk Oblast, Serhii and his comrade Mykola Saiuk perished.
Serhii was buried in the village of Studianka, Dubno Region.
The deceased left a mother and a father.
Serhii Kochetov was posthumously decorated with the Medal of the Defender of Motherland.
According to the Presidential Executive Order № 58/2017 on March 10, 2017, he was posthumously awarded the Third Class Order For Bravery “for valor demonstrated in the protection of the state sovereignty and territorial integrity of Ukraine, fulfillment of the active duty”.