Do you recommend breaking down your estimate to include the number of hours spent on certain tasks as well as breaking down each item?

It’s fine to breakdown your estimates, but to much breakdown will cause the client to pick apart the estimate and try to cut time and pricing. However, it is a good idea to place the amount of time and then state if the client goes over a certain amount of time that they will be billed for additional hours at your rate. My suggestion is to give the client a base price and then list the total time for the project. Then state the time overage costs to the client. Clients can be overwhelmed and not understand what you are breaking down in your estimate, they just want you to get the project done for a good price. Remember, the more simple the better.