If you're just a dude or a small start-up then sure, avoid analysis paralysis. But if you work at a bigger company, you have to test and bring in data to make changes -- otherwise, your stuff will lose out to other priorities.
also, you need to measure and test to know whether it worked, and thus to move quickly on to the next problem. If you can't demonstrate that a problem is solved, you'll likely be told to keep working on it long after it stopped being the most pressing issue.
