re: What’s the least amount a check would have to be for you not to even cash it?

I've got a couple from the IRS as over-charges they claimed in the letter. I've never cashed them, like $3 to $20. Just keep it when I gotta pay stupid amounts and remind myself they might just refund me. A couple years ago I got a letter from IRS stating that I overpaid $24,000+ and the wrote me a check. I didn't wait 5 mins before calling CPA and cashing it. CPA said they have no clue how the IRS arrived at that conclusion that I overpaid them but I sure didn't argue. It had to be the IRS mistake bc I sure get on my CPA to recheck before I write any large check to IRS. Check cashed.