How long to keep VOR check records?

So here's a question I had never thought of until getting my
instrument rating and owning an IFR-equipped aircraft: how long
should records of VOR checks be retained? Do they need to be
retained at all? Can the FAA come to me and ask, "Remember that
IFR flight to SLO you made 2 years ago? Show us the VOR check for
that flight."

This came to mind because the next VOR check entry will fill up
the form I have been using, and I'll have to start a new one. So
I have to decide whether to discard the filled sheet, or save it
somewhere. Is there any value to saving these with the aircraft
maintenance records?


Happy landings,
Ross Oliver