Going from sharing a one-bedroom place to living in a loft to two people living in a house to me having my own place by myself has kind of mirrored my career... small steps to bigger, to bigger, to now having a steady job.
It's a question of spreading the available energy, aerobic and anaerobic, evenly over four minutes. If you run one part too fast, you pay a price. If you run another part more slowly your overall time is slower.

