Oftener

Men, as well as women, are much oftener led by their hearts than by their understandings.

Source: tatoeba (757002)

A street in Constantinople is a picture which one ought to see once—not oftener.

Source: wiktionary

There were more sheebeens in Inverara than churches, which of course was natural enough, for alcohol cannot be put into a condensed state like the Grace of God, to be consumed on or off the premises. It takes up more space and has to be consumed in greater bulk and oftener in order to produce the desired effect.

Source: wiktionary

The heavy duty carburetor oil bath cleaner oil should be changed and the oil reservoir cleaned every 5,000 miles or oftener if driving conditions warrant.

Source: wiktionary