Cutting out a section or replacing the slab
When the trouble sits in one spot, like a sunken panel by the garage or a cracked square of patio, cutting it out along clean lines and pouring a new piece usually makes more sense than tearing out everything. If cracks run across most of the slab or the whole thing has settled, a patch just leaves new concrete next to old trouble, and I'll tell you replacing it is the better money. Either way, the base underneath decides how long the new piece stays put.

