You need to measure hot-neutral to make sure you don't have a "lost neutral".
If you aren't checking neutral, then you're just presuming everything in the neutral wiring is OK. But that attitude is prevalent -- in fact, people who have lost neutrals have a great deal of trouble convincing some professionals that they really have a problem! They're seeing 135V/105V on the two phases, and the electrician and power company are like "you're measuring it wrong, see? 240V across the outer poles."
If neutral wiring were that unimportant, it wouldn't exist.