If it ain’t broke, fix it till it is

if it ain't broke, fix it till it is

An ironic expression intended to warn against damaging or ruining something that is perfectly fine by fiddling or interfering with it too much. A humorous play on the phrase "if it ain't broke, don't fix it." Of course the school board wants to change the grading system because if it ain’t broke, fix it till it is, right?
See also: fix, if, till
Farlex Dictionary of Idioms.

If it ain’t broke, fix it till it is

and IIABFITII
sent. & comp. abb. Don’t leave well enough alone.; Just keep tampering. (A play on If it ain’t broke, don’t fix it.) Does it work too well or something. You must say if it ain’t broke, fix it till it is. Leave well enough alone.
See also: fix, if, till
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • intent on (doing something)
  • intent on doing
  • could do without (something)
  • could/can do without something
  • what do you know, (well)
  • last of the big spenders, the
  • the last of the big spenders
  • fiddle with
  • fiddle with (something)
  • the shame of it (all)