The purpose of the home appraisal determines which party pays for it. You’re generally responsible for the cost if you need to know the current value of your home to refinance your mortgage, though in some instances the lender will pay for it. The buyer pays for the appraisal when they are applying for their mortgage.

In most cases, installing a tennis court on your property will drive up your property taxes. Property taxes are determined, in part, based on improvements made to your property, which includes anything with a permanent foundation. Since most home tennis courts include a large concrete foundation, your property taxes will likely increase following the installation. A general rule of thumb is that if your project requires permits—like for a foundation or fencing for a tennis court—then your property taxes will be affected.

Wainscoting isn’t a design element that can be directly tied to an increased house price. Despite that, it is a highly marketable element that can generate significant interest from potential buyers who enjoy the style, and is relatively inexpensive to remove for those who don’t. If you are on the fence about paneling, just know that it certainly wouldn’t result in depreciation of your home’s value—usually the opposite. 

Basement bedrooms can count toward your room count and the square footage of your home on an appraisal if they’re fully legal, which means they have proper ventilation and points of egress, as defined by your local building code. Simply partitioning off a space for a bedroom in an otherwise unfinished basement that isn’t a legal living space won’t affect your appraisal value.