You might need to tension it in about two years from now, and after riding it just about every day in all sorts of conditions. Otherwise, leave the wrench that came with it in your toolbox and resist the temptation.

You will know if the saddle needs retensioning if it becomes like a hammock, and that often is caused by their owners using mink oil or some other non-authorised method of "breaking in" the saddle. In that case, retensioning is almost pointless because the saddle will effectively be ruined and won't last the expected 40+ years.