I guess that it depends on your reason for retesting. If you think that the prior results were less than valid for any reason or if he would need higher scores to get into some specific program or if it would change the decisions that you are making for his education if the numbers were much different than before, then it might be worth redoing.
Dd#1 was tested at 7 yrs 4 months and it was recommended that we retest b/c she was coming off of a really bad first grade year (she was mid 2nd when tested) and froze on some of the timed segments. Her scores within subtests ranged from the 25th percentile (on a timed part that she totally refused to complete) to the 99.9th percentile. Overall, her IQ came out in the low 130s, though, so she has qualified for gifted programming at school and, coupled with very high achievement scores and a motivated personality, has done well with a grade skip. For us, the only reason we'd have to retest is if we felt that she was a 99.9th percentile kid across the board (DYS eligible) and I don't think that she is. It won't make any difference in terms of programs for which she is eligible unless her scores are a lot higher than previously tested and we are confident that they weren't inaccurately high, so we're just letting sleeping dogs lie.
In re to dd#2 we have tested twice and I can't say that we know where she falls still b/c she is so erratic. The things that were high the first time around were low the second time and vice versa. She's either barely moderately gifted or maybe profoundly so or even not quite gifted at all depending on which ability and achievement tests you look at b/c the scores change on all of those every time she takes them. With her we are also letting it be for now and seeing how the interventions in place in school and at home do in terms of her achievement scores. If we get to a point where her achievement levels off, we may retest again, but I am just not sure about spending the money on it honestly.
