With interest rates low and consumer debt down from high levels, they say, conditions are ripe for an automotive replacement cycle.

Right now, because of the difficult economic environment, the replacement cycle has slowed dramatically.

This kind of replacement cycle doesn't happen in a vacuum.

It is my sense that replacement cycles for products like routers are extending, from three to five years.

Ms. Ask tied the increase to the average replacement cycle for laptop computers of three or four years.

For example, instead of replacing each of its 409 buses every 12 years, it went to a 55-year replacement cycle.

Shortening the replacement cycle has many critics as well as supporters.

The intergovernmental panel, in a draft report, said there would be at least two replacement cycles over the next century.

We're already seeing longer replacement cycles in enterprise and consumer computing (mobile devices seem to remain an exception).

Computer sales, for example, could ebb and flow with standard replacement cycles, or be pegged more directly to new software releases.