Long enough. [ It is his immediate answer before he decides to give a more truthful one. ] Only a few months.

Like any displaced plant... you need only put me in the ground and give me some nutrients to settle. [ That is the life of a mercenary. But it isn't the whole truth, either. His purpose is missing; he would have joined Zenith to revive the Doctor, but he knows what the Doctor wants from him. They would want him to revive Terra. The contract is not yet broken and by his honor as a Sarkaz and man who gave his word, he refuses to break it. ]

It won't take you long to figure out things here, either.