U Sco's eruptions are caused by the process described above, but because of some particular conditions in the system, they happen very frequently and pretty regularly, about once every ten years.
The U Sco system consists of a very massive white dwarf and a companion star that is starting to move through the end stages of its life. There are two key things happening there.
One, the conditions on the surface of a high-mass white dwarf like U Sco's are such that less hydrogen gas needs to accumulate before a nova eruption is triggered, and two, as the companion star evolves, it slowly expands, which causes the rate of hydrogen transfer between the two stars to be higher than usual.
So less mass is required to cause the eruption and​ that mass is accumulating faster than normal, so there are more frequent eruptions. Because the mass of the underlying white dwarf likely does not change much during a single eruption and because the mass transfer rate is also relatively constant, the amount of time for the necessary mass to accumulate is pretty consistent, and thus so is the time between eruptions.