The batteries last a long time and need only be replaced when they start to wear down.
These irregular features are wanting south of the limits of Pleistocene glaciation; there the rivers have had time, in the latest cycle of erosion into which they have entered, to establish themselves in a continuous flow, and as a rule to wear down their courses to a smoothly graded slope.
Moreover, the waves, I suspect, do not so much construct as wear down a material which has already acquired consistency.
And because titanium picks won't wear down like picks made from softer materials (plastic, wood, copper, brass, silver, gold, etc.), they don't produce a residue that will build up on your strings and clog them.
It is difficult to scratch the surface of laminate flooring, but over time, your German Shepherd running to meet you at the door may begin to wear down the melamine and eventually scratch up the pattern underneath.
