There is such a thing called "over-improvement for the market area". You may want to consult with an appraiser for what type and extent the proposed renovations, improvements, and/or upgrades contribute to the overall value of the property for the market area. The market dictates value. What is acceptable, what is considered an over-improvement or under-improvement in relation to market value for the market area. Renovations, improvements and upgrades do not contribute dollar for dollar in value of a property. To determine how much a renovation, improvement, and/or upgrade contributes to the overall value you need to research the market and apply matched pairs analysis. There are also less expensive materials that can give the appearance of higher quality finishes such as imitation granite counter tops, tile or hard wood flooring, etc. Consulting with an appraiser can also help determine any functional and/or external obsolescense that may need to be addressed.