It depends on the extent of the renovation and the conditions of the existing structure. Building from scratch may be cheaper in cases where extensive renovations are needed.
For personal residences, no. But if it's a rental or business property, you might depreciate the expense over time.
The most important part is ensuring that the construction or renovation is completed to the client's specifications, within budget, and on schedule while adhering to safety and quality standards.
The 30% rule suggests that you should spend no more than 30% of your home's value on any single renovation to ensure you don't overcapitalize on the investment.
For jobs under a specific dollar amount (typically $1,000), no. But for more extensive projects, a license may be required.