Right Effort: Approach Versus Avoidance
They shouldn't be done in isolation. It should be a comprehensive approach which is exactly why the Buddha taught the Four Right Exertions:


  There is the case where a monk generates desire, endeavors, arouses persistence, upholds &amp; exerts his intent:
  1. for the sake of the non-arising of evil, unskillful qualities that have not yet arisen...
  2. for the sake of the abandoning of evil, unskillful qualities that have arisen...
  3. for the sake of the arising of skillful qualities that have not yet arisen...(and)
  4. for the maintenance, non-confusion, increase, plenitude, development, &amp; culmination of skillful qualities that have arisen. ~~ MN 78 ~~