In any transaction, you want to build in plans for any possible contingency so if something should go wrong, you can cancel your contract without penalty.
For example, if you are also selling a home, you should make closing your own sale a condition of your offer. If you fail to include this as a contingency, you may wind up making two mortgage payments for a while.

There are other common contingencies you should include in your offer. One of the conditions of your offer should be that you successfully obtain suitable financing. Another condition should be that the property appraises for at least what you agreed to pay for it. During the escrow period you are likely to require certain inspections, and another contingency should be that it pass those inspections.