There is no general answer. Instead, whether or not you have to rebuild will be determined by the terms of your policy: read the policy, including any endorsements, amendments, etc. carefully to see what your obligations are. Not that it is very common for the insurer to pay a certain percentage of the expected repair or rebuild value--e.g. 50% to 70%--prior to the homeowner rebuilding, but to withhold the balance of the payment until the home is rebuilt and the final  bill comes in. Again, though, you need to look to the terms of your policy to see what your own requirements are. Good luck. Also note: if you sell the property before rebuilding, that commonly prevents you from getting a full recovery, so if you're contemplating a sale, but sure to check the policy for any terms like that.