Offer needed before property can be shown

[Wesley Wong]

We're interested in a duplex with tenants in WA and was wondering if it's normal that the buyer requires an offer to be presented and accepted before they are willing to show the place? Buying our home, we were able to view the place first before offering, even when there were tenants. This is the first time we're planning on buying a duplex for investment purposes and are not sure whether this is how it works when buying investment properties.

If an offer is required first, does this mean that our only way out of the contract if we don't like it is to wait and pay for the inspection?