Some problems introduce themselves before the sofa. A clipboard starts outside: stains under windows, a roof that sags, shared walls, a street that floods in photos from last spring, a price that dropped twice. None of these is an automatic no. Each one is a question you write down before someone offers you water.
Agree on two flags that would end the visit for you. If you do not choose them early, a sunny room will talk you out of them. The flags can be about the building or about the numbers. Write them. Take them with you.
A pretend example. Pretend your flags are 'I will not continue if the repair guess is over a year of leftover rent' and 'I will not continue if I cannot confirm the rent with two nearby homes.' A pretty tile does not get a vote.