They are soldiers for life. Pretty much all the surviving Jango-Fett based caminoan clones were serving as Imperial Stormtroopers, even when they became a minority among non-clones and non-FeddFett clones in the latter days of the Empire.
There were SOME clones who kinda-retired - one example was a sleeper cell of Soonier Fel clones (Carib Devist) in Zahn's Thrawn trilogy, who basically went native and became farmers - though they did come out of retirement to help Han Solo during battle for Bothawui. So if you're asking whether they were psychologically capable, then yes. But that was not the Master Plan for them.