Buying first Duplex, confirm rental history?

[Roger Wagoner]

Hello, I'm in the process of making my first offer on a duplex in WA state (Seattle area). I looked at a duplex today, and saw both units. One tenant I met seemed really concerned that her rent had just been increased by a $100 (on her month to month lease), which brought up a thought - how do I confirm the renters have actually been paying? If it matters, my plan will be to move into one of the units, so this may not even matter. Sorry if this is a common question that has been covered. I'm just starting to read through the forums now. thanks!