People have come to realize that housing is both consumption good and a savings vehicle.
Bridging loans can serve the same function if you are buying property at an auction.
If you have a good agent, this will take far less time but you need to make sure you look at any properties you are considering to ensure they are right for you.
Although we've just established that things will come up that you can't predict, you should know what the house will sell for before you make any kind of an offer.