your property.
Remove hazardous limbs or trees before damage occurs!
For example in our area we have a lot of "soft maples" like red maple, silver maple and boxelder that are notorious for having bad "form" (or shape from natural growth habit).
When you see a limb starting to grow out horizontally in a direction where it could someday break and cause damage...Better to "nip it in the bud"...and get it pruned back while its still a relatively small and cheap problem.
Furthermore, in many cases it is advantageous to remove an undesirable tree BEFORE it poses an serious hazard and replace it with a ornamental tree that will be in a better spot, mature to a smaller and more manageable size and give the added pleasure of seasonal flowering.