In addition to slow switching speed, another limitation was wear and tear.

除了开关速度慢，另一个限制是齿轮会磨损。

In addition to slow switching speed, another limitation was wear and tear. Anything mechanical that moves will wear over time. Some things break entirely, and other things start getting sticky, slow, and just plain unreliable.

除了开关速度慢之外，另一个限制是磨损。任何运动的机械都会随着时间的推移而磨损。有些东西完全坏掉了，而另一些东西开始变得粘稠、缓慢，而且完全不可靠。