I would try to avoid a project with a fixed price as much as possible, but if there needs to be a fixed price, the requirements and specifications should also be fixed. The problem with that is that the client usually doesn't realise what they need until they've started using the project. There are a few things you can try.
In the contract, specify a number of changes that can be done to delivered features without extra charge. For example, you could write down that the client can ask for 3 changes to the requirements without being charged extra. Take into account that these changes will happen when you're negotiating the price.
Similar to the previous point, you could agree on an amount of hours for unplanned changes. If you estimate the project in 100 hours, for instance, you could agree on 10 extra hours for changes. Once you've used them up, any further changes require a new agreement and should be paid separately.
Any other change is a new negotiation. If the client wants to change something, they can either (a) have it instead of another feature from the original agreement that hasn't yet been done and the developer deems of similar effort, or (b) pay extra to have that change implemented. This can be contemplated in the original agreement or it may require a new contract.
I would try to avoid a project with a fixed price as much as possible, but if there needs to be a fixed price, the requirements and specifications should also be fixed. The problem with that is that the client usually doesn't realise what they need until they've started using the project. There are a few things you can try.
In the contract, specify a number of changes that can be done to delivered features without extra charge. For example, you could write down that the client can ask for 3 changes to the requirements without being charged extra. Take into account that these changes will happen when you're negotiating the price.
Similar to the previous point, you could agree on an amount of hours for unplanned changes. If you estimate the project in 100 hours, for instance, you could agree on 10 extra hours for changes. Once you've used them up, any further changes require a new agreement and should be paid separately.
Any other change is a new negotiation. If the client wants to change something, they can either (a) have it instead of another feature from the original agreement that hasn't yet been done and the developer deems of similar effort, or (b) pay extra to have that change implemented. This can be contemplated in the original agreement or it may require a new contract.
What an awesome reply
I have found that the cost to fixed requirements and specifications is quite high.
Because they would be so many changes and unclear requirements.