for what it's worth

The phrase may have originally been used to qualify a statement of advice, opinion, or suggestion by referring to such a statement and describing it separately from making it.

for what it's worth

1. Considering what limited worth this advice, opinion, or suggestion might have for you; used to soften the presentation of unsolicited advice or information that may not be relevant.
   • 1877, Julian Hawthorne, Garth, page 343:

     Take my advice for what it’s worth—don’t marry Garth: marry some old fool.

   • 1908, Armand Both, The Half-smart Set, Frederick A. Stokes Company, page 276:

     “Well,” said he, “I have a suggestion to make, for what it’s worth.”

   • 1999, Bruce Northam, Brad Olsen, In Search of Adventure: A Wild Travel Anthology, →ISBN, page 21:

     There were seven of us from America, and, for what it’s worth, I thought it was a fairly impressive group.

   • 2005, Jennifer Rosen, Waiter, There’s A Horse In My Wine, →ISBN, page 253:

     For what it’s worth, the same holds true for fish bowls: overfill and you’ll suffocate the guppies.

"For what it's worth" can be used to emphasize humility by prompting the reader/listener to provide their judgment of worth against the statement being made; i.e., it may be useful information, it may not be, or perhaps differs from that the recipient's opinion.

• FWIW

• two cents' worth

• penny for your thoughts