Andy Grove talks about this in his excellent High Output Management, where he asks the question: how should knowledge managers (senior ICs) and people managers spend their time?

His answer is: on high leverage activities. Instead of fixing a small bug that affects a few customers, fix a big one that impacts revenue; train others to be better engineers, multiplying their future output; improve the process your team uses to build product. Essentially, look for activities that multiply output, rather than add to it.