The optimal service life of a mine is discussed theoretically from economic point of view by analysing the cost and benefit.

本文采用成本与效益分析的方法，从经济上对矿井合理服务年限的定量问题，作了理论上的探讨。

youdao

As long as the data of failure time, failure time interval and maintaining cost are collected in operation of equipment, the optimal service life of equipment can be determined.

只要在设备的使用过程中注意收集设备的故障时间、故障间隔时间和维修费用，就可以确定出设备的最佳使用寿命。

youdao

Plextor continues to promise optimal service for its customers by registering for VIP membership at Plextor official site.

ENGADGET: Plextor M5S SSD coming mid-July: healthy speeds starting at $99 for 64GB

"Clearly that is not an optimal customer service experience, " says Alex Dudley, a Time Warner Cable spokesman.

WSJ: The Wait-Time Misery Index

OPTiM's Optimal Remote service, used by over 12 million, also helps Japan-based wireless providers remote operate customer phones to resolve IT issues.

ENGADGET: OPTiM outs wireless smartphone-to-smartphone screen sharing and remote control app for Android