When you can stand in your yard and visually picture the trajectory of a limb or of a whole tree in a heavy thunderstorm, and that trajectory includes a part of your home, you can make yourself sacrifice an apparently healthy tree much easier.  That doesn't make it pleasant to do, but the alternative isn't acceptable either.   We have a large ash tree near our garage that's in that status now......it either needs a radical trimming or removal altogether.  For most people planting a new young sapling, it's very hard to imagine the final shape and size that tree will achieve in 20-30-40 years or more.