время от времени

1) General subject: (every) once in a way, (every) once in a while, at intervals, betweentimes, betweenwhiles, eftsoons, ever and again, ever and anon, every now and again, every now and then, every once and a while, every so often, from time to time, now and again, now and anon, now and then, off and on, on and off, on occasion, on occasions, once and again, one time and another, periodically, sometimes, sporadically, occasionally, every once in a while, in between times, intermittently, incidentally

2) Rare: sometime

3) Chemistry: at times

4) Insurance: Occasional

5) Business: now for then

6) Makarov: at odd times, once in a while