As an experienced AirBNB customer, what do you do when a unit goes bad and your out in the street? Do you just eat the extra high cost of booking the same night somewhere else?

I don't think I've had one go bad so as to not have a bed for the night. Having one go bad 2 days before you arrive and having to rebook, or having one that is really bad that you just can't stay at any longer (and then yes, you eat the high cost).

Doesn't happen too often though.

I've never had something go that bad.

I had one experience where we walked away the next day and opened a support ticket due to misrepresentation and a landlord who was mentally unwell and scary. AirBNB dragged their feet a little but did refund us fully within 24 hours. In that case I just booked something new and it was all good.

I've never had someone cancel on me on AirBNB.