This is a common question I get from realtor investors and homeowners, and my response to that is a resounding YES. Here are five reasons why having plans for your project is a wise investment.
1) Renovation plans with a comprehensive scope of work can help the contractors bid more accurately.
2) Having a good set of plans that display the final planned floor plan will save you a lot time explaining it to every contractor over and over again.
3) Reduces the number of contractors' change orders. When they don't have any plans, they are most likely to overlook thinks to bid on due to miscommunication. These change orders will raise your numbers and probably cause you to loose money.
4) Demolition work, removing interior walls, relocating windows, and most other construction work required city approval. Many homeowners renovate their homes without getting approvals because they believe no one would notice. The issue with this is that you could be jeopardizing the structural integrity of your house by not obtaining an engineer letter or plan approving the construction. Realtors tend to be a little different; they can do the construction work without permits as well, but once the inspector comes around and sees that the house has been fully remodeled, they will ask you to submit a set of plans for permitting.
5) Spend money up front in order to save money later. A set of plans allows you and the contractors to provide feedback on best construction techniques, materials, and potential problems that could arise during the construction process.