once-a-decade

At least once a decade, Colonel Qaddafi fomented shocking violence that terrorized Libyans.

The group's results also received a boost from the London Festival of Stamps, a once-a-decade event that took place in 2010.

It requires districts to have the same population, so that their boundaries must be redrawn after every census (ie, once a decade).

Depending upon the vehicle you drive, your spark plugs may need to be changed as often as yearly or as rarely as once a decade or so.

Before the Depression, financial panics were a regular part of life. They occurred about once a decade.

His memoir-cum-elegy for the American Southwest is worth reading once a decade or so.

Rules limit citizens to jury service once every few years, and in most places citizens serve far less frequently -- perhaps once a decade.

The changelings select carefully, for such opportunities might come along only once a decade or so.

Even tinier, isolated cells exist elsewhere in the region, erupting perhaps once a decade.

Dozens of banks have built towers but the height crown has changed hands less often, about once a decade.

The literary magazine has revealed its once-a-decade list of the 20 most promising British writers under 40.

That logic fails about once a decade.