Random writing thought: no description vs too much description

I'm reading Old Man's War right now by John Scalzi. It's not a bad book; has a interesting premise for a sci-fi. It was Scalzi's first book so maybe that has something to do with it, but I'm finding he does very little description or too much, somehow at the same time. He often has the main character telling the fate of his friends so it's not seen first hand but it's a giant info dump at the beginning of a chapter. I don't find this too annoying but I have noticed he doesn't bother going into too much detail about people's appearances or the places they visit. Halfway through the book and it feels like most of it has been huge chunks of dialogue.

It only bothers me because it's something I struggle with in my own writing. How much detail and description should you give the reader? Scalzi doesn't reveal much about the main character John Perry except that he has brown hair. No description of what he looks like, how tall he is, etc. But is it really necessary to give all that? Is it worth it to give an entire paragraph describing what a character is wearing? I find it depends on the character. Like, if I'm writing Inara, she'll notice what someone is wearing because it's in her character, but if it's someone else or something original, it becomes boring. It's always hard to find that balance.

So it lack of description: lazy writing or effective writing?