My son has two middle names, and I kind of regret it.
I was never a huge fan of double middle names, but at the time we were torn between the two (both significant family names). Now that we are having another boy, I really wish I had given my first son the one middle name, and then used the other one for this baby.
I have an ethnic middle name so it's "2 names", but I'm not a fan of 2 middle names like mary jo etc. My friend's children have names that are 5 names long. It looks hilarious on paper because their names are so long. If you want to it's totally up to you, for me personally I'm not a fan.