On occasion, I'll offer to do a couple of extra sessions for an individual or child. Some break points are better than others in my opinion.
By the end of 15 sessions (or 30,000 reps) most students have gained the researched amounts of gain, but I have my own favorite stages of training to take breaks. IM can be an almost endless training program as I can always load tasks to increase difficulty and work new pathways. Therefore, I've identified some specific goals that I like to reach before taking a break.
IM gains are cumulative. Each and every day neuronal pathways change (neurogenesis) as long as you are engaged. If you are just 'going through the motions' and not as engaged, then you are increasing the blood flow to those areas of the brain (angiogenesis), but may not be driving change in those neuro networks, still positive, but not as positive. Every child has times of very good engagement, and less engagement. The more engagement, the more the IM numbers change. I schedule 3 extra days in most groups to allow for missed sessions or for when a child has not reached a level I desire for them. The other students in the group can benefit from these 'extra' sessions if they want to at no extra cost. I don't always use these 3 days either, it's at my discretion according to the individual members of a group.
What gains you might see: Maturation is the general term I hear from many parents about IM gains. They often say, I'm not seeing any specific areas of gain, but my child just seems to be maturing. Maturation is an IM gain. The average parent is simply not trained to observe the subtle but extremely significant changes. If you look closely, the changes fit into very specific categories, the most common being
focus/attention
initiation
cognitive flexibility(the ability to change gears, see the world for someone else's perspective, coming when called, and trying new activities/foods)
metacognition (self analysis, self awareness)
coordination gains
increased verbalization - maybe even more dialog (back and forth conversation) where as before it was mostly monologue (talking about what's in their own brain)
time awareness
faster completion of tasks
increased emotional stability
sleep pattern gains if that is a challenge
There are more, but these are probably the most common gains that people report.