With regards to oversizing your inverter for your solar panels so you can add more later, has anyone actually done this and added more panels with out replacing the inverters or adding a new inverter?

Given the rate at which solar panels are improving it tends to become difficult to find matching panels for the rest of the array after a few years. And given the panels that are already on the roof will have degraded somewhat even if one finds perfectly matching panels they may not preform to there full potential.

@traderstu I assume the 3rd MPPT on each inverter is what you would plan to use if additional panels were added later? The typical advice has tended to be oversize the panels as the inverters tend to be more efficient closer to there max power and secondly the extra panels substantially increase the amount of power you get in winter and extend the peak of the solar day in summer.