Hello everybody how severe does a serial number repeat have to be for it to be valuable
I am not sure what you mean by “how severe” but repeaters should be:
A) in great shape (like AU to UNC) & not VG to VF unless they're tough repeater-radar, eye-catchers or a rarer/tougher older series*
B) Two digit (repeater-radar) such as ABABABA # pattern will be sought after before Three digit repeaters (ABCABCA # patterns)
C) The higher the # of digits in the serial # usually means tougher odds to find one & higher premiums so 3 digit BEP (USD 8 digit) radar will often fetch more than a CAD (7 digit) or a 6 digit (& smaller #) radars.
Here's a fun thread where some of us shared some radars & repeaters (scroll to the end). Scroll down to read about some of the other special serial numbers collectors often seek too. I don't think some World radars (nor repeaters) have caught on like they have in North America & other nations.
*I saw a VG-F 1937 $10 note go for about a $700 & was pretty surprised at that since the note was a bit over graded by the auctioneers & the number was nothing special.