For what purpose? If you have too many pixels, obviously you are going to need to downsample...it's not always a clear cut case in the event you don't have enough pixels...but the question as you asked it doesn't make sense...
I was thinking how to best match camera sensor resolution to a given printer size for optimal print quality.
Say I have a 24 inch printer and want to make the best possible prints at 3 different sizes: A1, A2 and A3. For an A2 print (approx 24 inches on the long side) I would need some 31 MP to print at 300 dpi with native resolution. I could upres this 100 % to make a A1 print (24 inches on the short side), and I could downsample 100% (or would that be 50%) to make a print size A3.
Alternatively I could have a sensor with some 65 Mp and be able to print A1 at native resolution with 300 dpi, and have to downsample 100 % (50%?) to make an A2 print and downsample 200% (100%?) to make an A3 print.
What would make the better print in the respective sizes?
(sorry about the confusion on the downsamling %, being an early bird it is way past bedtime here in Norway and at that time my brain goes into som kind of reduced capasity mode... :-)