The great thing about leather as an upholstery material is that cuts, tears and holes are easily repairable, if you know what you are doing. OK, you want to know exactly what kind of damage can be repaired. One big point here,
Generally in a high use area like a seat cushion or arm, tears should not be over 2″ in length. As for holes with missing leather about the same size. On side and back panels the damage can be larger but there are limits.
In high use areas the repair will need to stand the test of time and still look reasonably good. If the damage is larger than 2″ consider having the panel replaced with new leather.
Unlike fabric, leather is a mish mash of very small fibers held together as it were by small hinges. When leather gets ripped or torn, the tear will not travel or unravel like fabric. So if you need to wait before getting it repaired it will generally be ok.