Yes, installing a tennis court can be a worthwhile home improvement project that adds value to your property. The potential increase in value can range from $20,000 to $150,000, and in some cases, the return on investment can cover more than 60% of the installation cost. However, the impact on value heavily depends on the size of your property. For homes with multiple acres, a tennis court is often a valuable amenity. In contrast, for homes on smaller lots, installing a court can decrease the property's value because it consumes a significant portion of the usable yard space. It's crucial to consider your property size and the remaining usable yard before proceeding.

If installing board and batten fixes an issue with the home, it could increase the value, but it isn’t commonly installed for that purpose. Board and batten is an aesthetic choice and, like most aesthetic choices, will do little to raise your home’s value. That being said, certain design elements can help attract more buyers, even if your home’s price won’t see a noticeable bump. 

Yes, appraisals are often used for property tax appeals, estate planning, and determining market value.

Yes, built-in bookshelves can be worth the investment and can add value to your home, especially when constructed from high-quality, timeless materials like luxury hardwood. They offer a practical and stylish storage solution that utilizes wall space effectively. While they cost more than store-bought units, the custom fit and potential to increase your property's resale value make them a desirable feature for many buyers, particularly for homeowners with large book collections. For the best return on investment, consider having them professionally built.