Keeping your trees trimmed is not just about safety. Certainly, a tree falling or a large branch falling can be dangerous. But an unpruned tree can also simply damage the value of your property, and impact the values of your neighbors’ properties as well.
What are the reasons for this?
Potential buyers may object to your trees’ proximity to the house structures. Having trees that grow close to your windows or walls can pose issues for appraisers as well as the potential tenants. These trees can interfere with the drainage and the gutters, and can pose problems with the siding or brick work. Keeping the trees at a manageable distance can prevent these difficulties.
Something else to consider is the amount of light you are blocking from garden and lawn areas. If you block sunlight from the south-facing parts of your yard, it can be the equivalent of having a brick wall blocking the sun from whole sections of your property. If your buyers are interested in growing vegetables, they may assume they would need to pay for tree removal.
Home insurance can factor into this as well. Some insurance companies require trees to be a certain distance away from structures, and may raise rates if growth is happening too close to the foundation, or too close to windows.
A general rule to consider is that a tree should be as far away from the building as it is tall. If a tree is 10 feet tall, it should be 10 feet away from the wall. If it is 20 feet tall, it should be 20 feet away from the nearest wall. This way, if it falls over from its base, it will stay clear from the building and not crash into a wall.