Whole new studies are being created with the discovery of planets outside our star system. What’s even more amazing is we haven’t found a “duplicate” of Earth. I believe Stephen Hawking suggested that Earth my be the only type of it’s kind in all the galaxy. Much like each human on Earth is an individual so are the planets. Similar...but different.
We really do live in a very narrow band of environmental requirements. Something as small as a couple percent more x-rays reaching a planet’s surface would render it uninhabitable for us. The same can be said about the balance of gasses in an atmosphere.
In reality, finding life would actually complicate things for us in the sense that it would likely render a planet useless to us even if we couldn’t live there ourselves.
Robert Forward’s “Saturn Rukh” lays out a pretty likely scenario of what would happen if we found even primitive life. In the book the crew goes to Saturn to test the viability of mining helium as a fuel source. They find that it’s viable but impossible due to the fact that there is primitive but intelligent life.
Lifeless rocks really are the most usefull things for us out there right now.