k-5 was rated at 100,000 shutter actuations I believe. However, that is only a suggested average. Some will go longer, some less. It also depends on your shooting style, lots of fast burst might cause more wear and tear than only shooting single shots. Shooting at very fast shutter speeds might wear out the mechanism faster. Temperature extremes, dust and dirt and and shocks might also have an affect. And note that the rating is (I think) for the shutter mechanism, so if something else fails that really is not what the rating is looking at.
I got about 40,000 if I remember right on my k-5 before repair.
This is interesting:
pentax k7 | Camera Shutter Life Database