Jobi's examples are spot on, but they may be very prejudiced. Which means, he may have gone thru 10 or more individuals, to come up with a pair.
I would indeed bet on Jobis pairs actually being a pair, but I would not bet on the ones that did not meet this criteria.
The case becomes, does the one in your hands, meet this criteria? If it does, then fine, but many times it does not.
We have had clutches of similar monitors, Albigs, meet this criteria in two weeks after hatching. Or not until two or three months. But from that time on, they mostly meet this criteria.
Which is funny because I doubt many Savs reach our shores at under two months of age. Of course, it could be more about development then actual age. Cheers