Well done is twice done.
Franklin suggests that work completed properly has greater value than work done carelessly or incompletely. A task carried out well achieves its immediate purpose and also avoids the need to return later to correct mistakes. In that sense, doing something well is “twice done” because one careful effort can accomplish what poor workmanship might require two attempts to achieve.
The saying is not an argument for perfectionism or excessive delay. Its broader point is that reasonable care at the outset can save time, effort and expense later. Franklin therefore connects quality with efficiency rather than treating them as opposites. Whether applied to practical work, professional tasks or everyday responsibilities, the proverb encourages thoroughness where mistakes would otherwise create unnecessary repetition.