Getting close to the 6-month mark

In the back of my mind is always the guideline that a dog will be at about 80% of where they are going to be at the 6-month mark.  At this point, we are at 5 1/2 months and Nathan is not recovered to the point that I would want to consider 80%.  So, we continue to work hard with him each day to ensure that he makes progress each week.  In fact, he does make progress each week. Some weeks, the progress is small, some weeks, it's amazing.  It's Sept 10, and Nathan can now do 3 5-minutes unassisted walks each day.  He is now steadier, he falls over significantly less as he walks unassisted.  Today, on our morning and afternoon walks, he walked 1-2 minutes further unassisted.   I worry each day about him plateau'ing.  I know that day is inevitable.  We have exactly one week until our trip to Cancun.  We want to have Nathan as healthy as possible for the vet tech who will be staying at our house taking care of the boys.