IDIOMS

let the perfect be the enemy of the good

(idiomatic) To insist on the total realization of a goal and reject any compromise, thereby decreasing the chance of achieving even a part of that goal.

Example: 1960: Macdonald College, The Macdonald Farm Journal, volumes 21–22, page 7 (R. J. Cooke)
  More data and more analyses will provide better information for the future, but we dare not let “the perfect be the enemy of the good”.
1973: Official journal of the European Communities, issues 165–169, page 161
  Of course they are far from perfect, of course we are more than ready to welcome constructive improvements to them, but I beg Parliament and also Member Governments not to let the perfect be the enemy of the good.
1978: Welfare Reform Proposals: Hearings Before the Subcommittee on Public Assistance of the Committee on Finance, United States Senate, Ninety-fifth Congress, Second Session, volume 3, page 572 (United States Government Printing Office)
  Incremental reform can move us forward and can improve the plight of the poor. I hope we do not let “the perfect be the enemy of the good” in welfare reform.
2007: Chris Brian, The Politics Show, Wales regional report
  But we shouldn’t let the perfect be the enemy of the good.