There's a very narrow corridor between not enough capacity, which is bad for reliability, and too much capacity.

But, after all, one cannot, at sixty-two, look back down the corridor of one's life and not have some doubts about the journey one has made. The doors which one opened are now all closed. The doors one did not dare open remain shut. The corridor is dark; only ahead is lighter. So one turns and proceeds in that direction. To go back is madness. To turn left or right, at this stage, is both exhausting and dangerous.

The course of the SPD and its reliability is not so clear anymore,

You can't give real responsibilities to the shady shoulders. The weak may learn, but a shady person will always fall flat on face.

This history sets forth the only true account of the adventures of a daring Tipperary man named Darby O’Gill among the Fairies of Sleive na mon. These adventures were first related to me by Mr. Jerry Murtaugh a reliable car driver who goes between Kilcuny and Ballinderg. He is a first cousin of Darby O’Gill's own mother.

The Encyclopedia Planaria, in forty-four volumes, is not portable, and after all, what is entirely reliable unless it's dead?