The damage caused by leaking pipes can range from just a little wood warping or swelling to a designated area in the cabinet, to more serious damage like the swelling or buckling of the floor, wall studs, and sheetrock. All of this wetness can lead to costly wood repairs and even worse, mold damage which is extremely unhealthy.
It is those small drips or sprays that can cause the slow occurring water damage in one specific spot under your kitchen or bathroom cabinet. Most of the time, if caught early enough, the damage might not be so bad. The thing with small leaks is that some only happen while the water is in use and will stop when it is not, like the drainage pipes.
When water is running through them, they leak. These leaks can be harder to detect because they can wet a spot on the floor of the cabinet or surrounding wall and then eventually dry out. You may open and close your cabinet door many times before you notice a wet spot.
Water leaks occurring from the pipes that supply your water are a different matter. Since they have water flowing into them at all times, the leaking will be constant. These types of leaks are likely to be noticed a lot sooner than those from drainage pipes.
Which ever pipes you have that are leaking, the sooner they are repaired the less damage they are likely to cause. Whether or not you attempt to repair these leaks yourself might depend on where it is. If you can see the leak itself, you can probably fix it fairly easy.
If the place in the pipe that is leaking is behind the wall, it will not be as easy to fix. You might want to call the plumber if this is the case. Sometimes just simply tightening a fitting on a pipe will stop a leak or applying pipe cement when the pipe is dry. If you have old metal piping, a hole can occur from rust and the entire pipe should be replaced.
If you have pvc pipes, sometimes the seals need replacing or using plumbers tape inside can correct the problem. Home improvement stores offer complete pipe replacement kits for under kitchen and bathroom sinks. These kits are relatively easy to install and can be done by almost anyone with a little patience who wants to save the money you would have to pay a plumber.